Several Years of Tax Returns and BAS Not Lodged: What Happens and How to Catch Up

What the ATO actually does when several years are missing

Most people in this position have one question they are afraid to ask: how much trouble am I in? Here is what the ATO can do, in the order it usually happens.

Failure to lodge penalty, per return

Every tax return and every BAS is a separate lodgement. The ATO can apply a failure to lodge penalty to each one. The penalty is worked out in penalty units for each 28 day period (or part of one) that the document is overdue, up to a capped number of periods, and it is multiplied for medium and large entities. Three years of returns plus twelve quarterly BAS is fifteen separate documents that can each carry a penalty. That is why the number people get quoted sounds frightening. It is also why remission matters so much, which we cover below.

Two things soften this in practice. The ATO does not always apply the penalty, particularly on a first offence or where a refund is due, and it has discretion to remit it. The penalty also sits on the lodgement, not on the tax, so a year with no tax owing can still attract one.

General interest charge on tax owing

If a year turns out to have tax payable, general interest charge (GIC) runs on the unpaid amount from the original due date, compounding daily, until it is paid. On a year that is six or seven years old, the interest can be a meaningful fraction of the original tax. GIC can also be remitted in some circumstances, but it is harder to argue than the lodgement penalty. The practical point is that interest is the cost of waiting, and the only way to stop it growing is to lodge and start paying.

Default assessments if the ATO guesses your income

When the ATO has data showing you earned income (employer reporting, bank interest, contractor payment reports, sale of property or shares) and you have not lodged, it can issue a default assessment. It estimates your taxable income from the data it holds and the industry benchmarks it uses, and assesses you on that figure. Default assessments are almost always higher than the real position because they do not include your deductions, your cost of sales or your GST credits, and a significant administrative penalty can be added on top. You can object, but the burden is on you to prove the correct figure, which means doing the work you were avoiding anyway, under time pressure and with the debt already on your account.

When it becomes a prosecution matter

Failure to lodge is an offence, and the ATO does prosecute. It does not happen on day one. It generally follows a sequence: reminder letters, a formal notice requiring lodgement by a date, a final notice, and then referral for prosecution if there is still no response. A conviction can mean a fine and a court record, and the lodgement obligation remains afterwards. Almost everyone who ends up there got there by ignoring every letter. Anyone who engages, even partway through that sequence, is normally dealt with administratively rather than in court.

If you have received a formal notice with a date on it, treat that date as real and get help now. If you have only had reminders, or nothing at all, you have time to do this properly.

The ATO 6 year rule in plain words

A lot of people searching for this page are hoping that after six years the old years simply fall away. They do not. There is no rule that cancels an unlodged tax return because enough time has passed.

The six year figure comes from a few different places that get mixed together:

• Record keeping. The ATO generally asks you to keep the records that support a return for five years from when you lodge it (some situations, such as assets held for capital gains tax, run longer). People round that to six, and assume it means the ATO can only look back that far. It means the opposite: you cannot throw records out until the return they support has been lodged and the period has run.
• Capital gains tax on a former home. There is a six year period attached to a specific main residence concession for a home you move out of and rent. It has nothing to do with lodgement deadlines.
• Amendment periods. Once a return is lodged, the ATO has a limited window to amend it (two or four years for most taxpayers, with exceptions for fraud or evasion). That protection only starts when you lodge. An unlodged year never starts the clock.

So what does it mean for you? Three things. First, the obligation to lodge every outstanding year is still live, and the ATO can require any of them. Second, you are not expected to have perfect records for a year that is eight years old, and a reasonable reconstruction is accepted. Third, the ATO does take a practical view on very old years where no tax would have been payable, which is where non lodgment advices come in. But that is a decision made year by year on the facts, not a blanket expiry.

The order of attack

Catching up several years is a project, not a single return. Doing it in the right order avoids rework, stops the ATO escalating while you are working on it, and gets the penalty remission request onto the strongest footing.

1. Get the lodgement list from the ATO. Log in to ATO online services through myGov (or have a registered tax agent pull it from their portal once you are linked) and look at the lodgement history and outstanding lodgements. Do not work from memory. People regularly discover a year they thought was lodged was not, or that a year they were dreading was never required. For a business, the list shows every BAS period and whether PAYG instalments were due as well. Note any ATO correspondence dates and any notice deadlines.
2. Sort the years into return required and non lodgment advice. A year where you had no income, or income under the tax free threshold with no tax withheld and no business activity, may not need a return at all. A non lodgment advice tells the ATO that and closes the year. Get this call right, because lodging a nil return that was not required wastes money and lodging a non lodgment advice for a year that did have income creates a bigger problem than the one you started with. For BAS, a period where you were registered for GST but had no activity still needs a nil BAS, not nothing.
3. Reconstruct income when the books are missing. This is the part people assume is impossible. It is not. The ATO prefill for each year shows employer income, interest, dividends, managed fund distributions, some government payments, and contractor payments reported by businesses in certain industries. Bank statements, which banks can reissue for closed accounts on request, show every deposit. Supplier statements and customer invoices fill in the rest. For a sole trader or company, the standard approach is to download every bank transaction for the period, code the deposits as sales and the outgoings as expenses, and tie the totals to prefill. A backlog bookkeeper can rebuild a ledger from bank data alone if that is all you have.
4. Do the BAS and the tax return for each year together. The GST turnover on four BAS should reconcile to the income on that year's tax return, and the PAYG withholding reported on BAS should match the payroll reported for the year. If you lodge BAS now and returns later, or the other way round, the mismatches trigger ATO questions. Work oldest year first so that opening balances, losses carried forward and instalment credits flow correctly into the next year. Lodge each year as it is finished rather than holding everything to the end, because every lodgement on file improves your position if the ATO contacts you mid project.
5. Request penalty remission, then set up a payment plan. Once the returns are in and the ATO has issued assessments, you know the real figure. A remission request covers every failure to lodge penalty across the catch up and sets out why the delay happened and why it will not happen again. Then, for whatever tax and interest is genuinely owing, propose a payment plan you can actually keep. The ATO is far more willing to agree terms with someone whose lodgements are all up to date. Missing a payment plan instalment can void the arrangement, so be realistic about the amount.

Common mistakes at this stage: lodging the most recent year first because it is easiest (and losing carried forward losses from earlier years), guessing income instead of reconstructing it, forgetting that a company also needs the director's personal returns done, and setting a payment plan before the remission decision comes back so you end up paying penalties that would have been removed.

How much does it cost to catch up each financial year?

Catch up work is almost always quoted per financial year, sometimes with a package price for the whole backlog. Nobody can give you a fixed number without seeing the lodgement list and what records exist, but the shape of the range is predictable.

Three honest points about cost. First, the fee is usually smaller than the penalties and interest that keep accruing while you delay, and often smaller than the refunds that are sitting unclaimed in the early years. Second, the first year is the dearest because it includes the setup and reconstruction; later years get cheaper once the pattern is established. Third, ask for a fixed price for the whole backlog, with a clear list of what you need to supply, before anyone starts. An open ended hourly quote on a ten year catch up is how people end up abandoning the project halfway through.

When a prior accountant is part of the problem

A surprising number of multi year backlogs start with an accountant who stopped lodging, closed the practice, fell out with the client over fees, or simply went quiet. Sometimes the client assumed everything was being lodged for years. Here is how to untangle it.

• Check what was actually lodged. Your lodgement history in ATO online services is the source of truth, not the previous accountant's emails or invoices. If a year shows as not lodged, it was not lodged, regardless of what you were told or paid for.
• Request your records in writing. Your source documents (bank statements, invoices, receipts, payroll records) belong to you and should be returned when you ask. The accountant's own working papers are theirs, but a registered agent is expected to hand back client records and provide copies of anything lodged. If there is a fee dispute, resolve it separately rather than letting it hold the catch up hostage. Registered tax and BAS agents are bound by a professional code, and a complaint path exists if records are withheld unreasonably.
• Revoke their authority. You can remove a tax agent's link to your ATO record through ATO online services, and when a new registered agent adds you as a client the old agent's authority is replaced. Do this before the new agent starts so that ATO correspondence and lodgement confirmations stop going to the wrong place. Also check whether the old agent was listed as an authorised contact for the business or as the address for ATO mail, and update both.
• Do not wait for the old file. A new agent can pull your lodgement list, prefill data and account balances directly from the ATO. Combined with bank statements, that is usually enough to rebuild the missing years even if the previous accountant never returns a single document.

If you relied on an accountant who did not lodge, say so in the remission request. Reliance on an agent who failed to act is relevant to whether penalties are remitted, and in some cases a safe harbour applies where a registered agent was given everything needed and still did not lodge.

Why a registered tax agent lodging the catch up usually lands a better penalty outcome

You can lodge old years yourself through myGov, and for a single simple year that is fine. For several years, especially with BAS, a registered tax agent changes the result in ways that are hard to replicate on your own.

• They can see the whole picture in one place. The agent portal shows every outstanding lodgement, every penalty already applied, the running account balance and the prefill data for each year, which makes the lodgement list and the non lodgment advice decisions straightforward.
• They can speak to the ATO on your behalf. That includes asking for a hold on enforcement action while the catch up is underway, which is often granted once the ATO sees a registered agent engaged and a plan with dates.
• The remission request is written properly. Agents request remission routinely and know what the ATO weighs: voluntary disclosure, the reason for the delay, your compliance history and the steps taken to stay compliant. A one line request through the myGov form rarely carries the same weight as a structured submission lodged with the full catch up.
• Reconstruction is defensible. If the ATO queries a rebuilt year, an agent's working papers show how each figure was reached. That matters if you are objecting to a default assessment, where the burden of proof sits with you.
• Safe harbour and ongoing deadlines. Once you are a client, future years fall under the agent's lodgement program with later due dates, and if a future delay is the agent's fault rather than yours, a safe harbour from failure to lodge penalties can apply.

The practical difference is usually this: a self lodged catch up gets the returns in and leaves the penalties where they fall. An agent lodged catch up gets the returns in, gets the ATO to pause while it happens, and comes with a remission request that frequently removes a large part of the penalties. On a multi year backlog, that difference is often larger than the fee.

Related pages if your situation overlaps: one late tax return, overdue BAS, backlog bookkeeping, and company tax returns.

What to have ready before you ask for a quote

You do not need everything. You need enough for a tax agent to scope the job and give you a price.

• Your myGov login so the lodgement list can be checked, or a screenshot of the outstanding lodgements and the account balance.
• Any ATO letters, especially anything with a deadline, a default assessment or the word notice on it.
• Your structure for each year: employee only, sole trader, company, partnership or trust, and whether you were registered for GST or had staff.
• What records exist: which bank accounts were used, whether statements can be downloaded, whether any accounting software was ever set up, and roughly what is missing.
• Why it happened, in a sentence or two. Illness, divorce, business collapse, a prior accountant who went quiet, or simply that it got away from you. This goes into the remission request and nobody is going to judge you for it.

Once you are up to date, the last step is making sure it does not happen again: a simple bookkeeping routine, BAS reminders, and an agent lodgement calendar for the current year.