A German man has been fined 208,000 euros ($326,000) for cheating at a supermarket self-service checkout.

Munich's district court convicted the 58-year-old businessman of theft for trying to pass off 47 euros worth of veal liver as fruit.

The man, who was not identified, had done the same thing three times before and also had past convictions for theft and tax evasion.

The court based the high fine on the man's monthly income of 24,000 euros ($37,600).

He was released from jail, where he had been held since the theft in December.

Munich court spokesman Klaus-Peter Juengst said the defendant did not appeal against the verdict, which was issued last month.

Supermarkets in Australia are also cracking down on the practice, with Associate Professor Gary Mortimer from the Queensland University of Technology saying there was $4.5 billion worth of retail theft in 2016.

He also said studies had shown customers felt more comfortable stealing from a machine than when they came into contact with a human being.

"We may under-scan a product, we may ring up a stone fruit and say it is potatoes," he said.

"Or we may compensate, and say if we are going to ring up our own groceries, that chocolate bar is going to compensate for my time and the big retailer can afford to do it.

"If we are dealing with a machine, it's not going to get its feelings hurt so we rationalise it that way."

NSW Police Detective Superintendent Murray Chapman said committing this kind of offence was a crime, no matter how small people thought it was.

"Even if it is the avocado and you think you're saving $2, it's still shoplifting," he said.

"It's still stealing, it's still a crime and if we catch you, or you get caught, you will be charged."

ABC/AP