Unpaid overtime sees Australian workers hand back about $130 billion a year to their employers, the Australia Institute says.

The Australia Institute's Centre for Future Work released a survey this week which found the average worker does 5.1 hours a week in unpaid work.

“That includes everything from going in early or staying late at work, to working through breaks, working through lunch, taking work home, answering emails in the middle of the night,” said the centre's director Jim Stanford.

“All the different ways that work is trickling into our everyday lives adds up to quite a bit of time.

Dr Stanford said this year’s figures were about half an hour more than last year’s survey found.

He believes the increase in unpaid work is a sign of “profound insecurity that most Australians feel about their jobs”.

“People are staying late because they want to keep their employer happy, they want to show they've got a good work ethic, they're hoping that they'll be able to keep their jobs,” he said.

“And that's exactly the same pressure that explains why Australian workers aren't willing, at this point, to demand higher wages from their employers either.

“That fear factor is inhibiting workers' bargaining power in the workplace.”