A man who stole a trolley full of groceries from a supermarket this week casually walked out with the goods, brazenly telling staff he wasn't going to pay for them.

A witness to the supermarket theft at Countdown Meadowbank in Auckland said staff chose not to restrain the man after confronting him about the non-payment.

The witness said he watched in shock as the man, aged 25-30, simply left the store without paying.

"I heard one of the staff say to him, 'You have not paid for those' and the response from the thief was, 'I'm not going to.'

"And he boldly walked out. He did not run, he walked. He appeared confident and relaxed. Obviously an experienced supermarket thief," the witness told the Herald.

At first, the witness was stunned supermarket workers did not do more to stop the man from leaving, but in hindsight said he understood their reluctance.

"At the time I found the response to this incident from supermarket management frustrating but on reflection, what can they do?" the witness said.

"There is always the huge fear that a person like this could have a weapon and if he had been physically challenged the outcome could have been disastrous."

Police arrive about 10 minutes after the man left the store.

Police have been approached for an update on the Countdown theft.

Earlier this year, Countdown's corporate affairs manager, Kiri Hannifin, said staff had suffered an increasing amount of abuse.

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The sometimes daily abuse ranged from verbal abuse for enforcing mask use, being spat at, and even threats on their lives.

Hannifin said Thursday's theft was an unfortunate reality for a chain of stores that "served more than three million customers a week across Aotearoa".

"The vast majority of our customers are honest, unfortunately theft is a reality in retail from time to time and we have a number of security measures in place to detect and prevent shoplifting," she said.

"These include CCTV, security tags on certain items, supervisors at check-outs, and security guards at a number of our stores."

Supermarkets were just one sector of retail targeting by thieves. Ram raids of dairies, liquor stores and jewellery stores have become a daily occurrence during the past six months.

Police have recently boosted patols around the city as ram raids have increased.

Police Minister Chris Hipkins said there had been about 150 arrests and 750 charges since February in relation to ram raids.

"Police are focusing significant investigative effort on the recent spike in retail offending, including ram raids, and have a good success rate in holding offenders to account."