After years of efficiency dividends and a cap on staffing numbers in the federal public service, anyone calling for more funding has their work cut out for them to get the attention of the wider public.

Some requests are more worthy than others, and I worry that the call from the Auditor-General for a funding injection for the Australian National Audit Office won't whip the populace into a frenzy, and like Joni Mitchell sang, we won't know what we've got 'til it's gone.

Funding for the audit office fell by $17 million between 2016-17 and 2019-20.

As the budget was reduced, the audit work required became more complex and expensive, and requests from government for new programs also ate away at the resources available for performance audits.

It meant there were six fewer performance audits completed last year than the year before.

The government has been told to expect fewer performance audits - and therefore less scrutiny of government decisions and spending - if funding certainty isn't provided.

What does fewer audits mean? Maybe the next time the government pays $33 million for a piece of land valued at $3 million, we won't find out. Or the procurement of a major IT system could be "deficient in almost every significant respect", but no one will check.

Many Australians do not realise how much they have to thank the audit office for. A report titled Award of Funding under the Community Sport Infrastructure Program is more widely known as "sports rorts", and the revelations that Defence equipment is 57 years behind schedule were contained in the 2019-20 Major Projects Report.

And these are just the eye-catching headlines. Of course, much of the valuable work of the audit office never makes it to the newspapers or the 6pm news. Ensuring annual financial reports are correct, conducting assurance reviews on emergency government spending and helping the public service learn from mistakes aren't sexy tasks, but they are important for good governance.

The long-promised federal anti-corruption commission appears to have been put off even longer, making the role of the audit office even more important.

Its powers to obtain documents mean nothing is out of its reach (including spreadsheets colour-coded by electorate). As other avenues for accountability and oversight like freedom of information are eroded, audits become even more valuable.

Auditor-General Grant Hehir doesn't approach newspapers making the case for extra funding. In fact, his office has studiously and politely avoided my questions for more information about funding issues for years.

Instead, Mr Hehir uses his few chances for public comment, including the office's annual report published last week, to raise issues like independence and funding for his office.

Last week we learnt he had written to Prime Minister Scott Morrison about the funding situation, calling for funding to be continued on a more sustainable basis to allow the office to fulfil its mandate and achieve transparency and accountability.

When Treasurer Josh Frydenberg hands down the budget on Tuesday night, funding for the Auditor-General is unlikely to make it to the speech, or even to the winners and losers list. But I will be looking for it, as should anyone who values oversight and accountability.