One Aussie shopper has brought the nation’s receipt laws under the microscope after they were asked to produce a receipt for a product they had bought elsewhere.

Posing the question to the AusLegal page on Reddit, the frustrated customer in said they walked into a Victorian Coles with a trolley full of groceries from Aldi.

“I had a trolley full of items I had bought at Aldi, and popped into Coles for a few bits,” the poster said.

“The lady at the self-checkout pointed at the 30-pack of Coke cans and demanded to see a receipt to prove I didn’t steal it.

“I said I didn’t have one, I never keep receipts unless it’s for an expensive purchase that I may need to refund/exchange.

“She continued insisting that I had to keep my receipts from other stores so that I could prove I hadn’t stolen.”

9News.com.au asked criminal defence attorney and author of Talk Your Way Out of Trouble, Jahan Kalantar, the question.

Turns out supermarkets have little to no power to demand a receipt from a customer.

“The law does not give private retailers like Coles and Woolworths any legal authority to compel you to produce proof of purchase for goods that you bought somewhere else,” Kalantar said.

”If the store thinks that you’ve stolen, they can request to inspect your bags, but security guards really don’t have much power; all they can do is get the police involved.

“If they keep people there against their will, if the Coles worker keeps you there, there’s a possibility that it might be a false imprisonment claim.”

Kalantar said most people would just comply and show their receipt to get out of the situation.

There is a bit of a grey area if you paid cash or don’t have a receipt, if they suspect you’ve stolen an item.

“I had one where the guy didn’t have his receipt, but he just opened his bank account and said here is the transaction, I couldn’t have taken it,” Kalantar said.

“But fundamentally, you are entitled to your privacy, just because you walk into a store and they have some assumption doesn’t mean anything.

“It’s very different if they’ve seen you on camera pocketing something, but there is no fundamental legal authority that a security guard can compel you to provide a receipt from a different store.”

9News.com.au has contacted Coles for comment.