Thursday is the deadline to submit tax returns although registered tax agents have until May to lodge a return on your behalf.

The catch is you have to be on their books by Thursday, so it's deadline day either way.

The country's leading accounting body CPA Australia is urging people to take action to avoid fines that come with lodging tax returns late - or not at all.

CPA tax lead Jenny Wong told the Savings Tip Jar podcast said the penalty is $313, going up to $330 for every 28 days the return is overdue.

"But the ATO understands life happens, so they don't usually penalise isolated cases of late lodging in practice," Ms Wong said.

"So, if you anticipate a delay, reach out to the ATO and they'll consider your individual circumstances."

Ms Wong warned for those who have a history of late lodgement, the ATO may not be as lenient as it is for one-off cases or those who have good reasons for submitting their returns after the deadline.

How to do your tax return?

Taxpayers can choose to complete their tax returns themselves using the pre-filled forms on the myGov website.

The government sources pre-filled information through employers, banks, health funds, and government agencies.

It's designed to make lodging a tax return as simple as possible, but Ms Wong warns it's vital to double check all the pre-filled data to ensure it's correct.

"You might have circumstances that change," she said.

"Your work circumstances could have changed so just ensure all the income is reported and the same goes with your deductions.

"Don't just copy and paste what you did with prior years because some people have been incorrectly claiming work-related expenses."

See also: What is the tax-free threshold in Australia?

What the ATO is looking out for

The ATO provides occupational guides on its website to help taxpayers understand what is claimable and what is not according to the work they do.

Ms Wong said the ATO looks closely at work-from-home deductions, so any claims need to be substantiated.

She warned those claiming expenses on rental properties also need to be clear on what repairs and maintenance are claimable and what are capital improvements that need to be deducted over time.

She said the more complex a person's earning activities and finances are, the more they can benefit from professional help.

"A tax agent or an accountant will not only have longer to submit your tax return, they'll ensure it's filled out correctly and accurately," she said.

Tax time, scam time

Ms Wong warned Australians to beware of tax-time scammers and not to engage with SMS messages, emails, or social media posts purporting to be from the Tax Office, or tax agents claiming to get you substantial refunds.

She urged people to watch out for grammar or unprofessional language, a giveaway that it is not an official communication.

She also reminded people the ATO has stopped using hyperlinks in their unsolicited messages to help distinguish them from fake ones.

"One of the more common scams is ATO-branded emails containing links to fake myGov sites," Ms Wong said.

"Scammers use your sign-in credentials to gain access to your myGov accounts and once they get access, they can make fraudulent lodgments, change your name, your bank account details so payments are redirected to scammers."

Anyone foreseeing difficulties in lodging their tax return or registering with a tax agent by Thursday can contact the ATO.

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