Around 8.5 million people claimed nearly $19.4 billion in work-related expenses in their 2020 tax returns.

Australian Taxation Office assistant commissioner Tim Loh says the COVID-19 pandemic has changed people's work habits, so he expects their work-related expenses will reflect this.

"We know many people started working from home during COVID-19, so a jump in these claims is expected," Mr Loh said.

"But, if you are working at home, we would not expect to see claims for travelling between worksites, laundering uniforms or business trips."

The ATO's data analytics will be on the lookout for unusually high claims, particularly where someone's deductions are much higher than others with a similar job and income.

"We will also look closely at anyone with significant working from home expenses, that maintains or increases their claims for things like car, travel or clothing expenses," Mr Loh said.

"You can't simply copy and paste the previous year's claims without evidence."

A "temporary shortcut method" for working from home expenses is available for the full 2020/21 financial year.

This allows an all-inclusive rate of 80 cents per hour for every hour people work from home, rather than needing to separately calculate costs for specific expenses.

"All you need to do is multiply the hours worked at home by 80 cents, keeping a record such as a timesheet, roster or diary entry that shows the hours your worked," the ATO says.

However, this is only a temporary measure, and for those wanting to claim part of an expense over $300 - such as a desk or computer - in future years, they will need to keep a copy of their receipt.

Australian Associated Press