AS more customers find ways to avoid paying full price at self-serve check outs, frustrated supermarkets and authorities are cracking down on shoplifting in NSW.

According to a report by the Australian Associated Press (AAP), retailers such as Coles say they're sick of being targeted by opportunists who lie about what they're purchasing to get a discount or who try and avoid paying at all.

“No matter how small you think it is, even if it's an avocado and you're saving $2, it's still shoplifting,” detective superintendent Murray Chapman said outside a supermarket in Zetland, in inner-Sydney.

Last financial year the NSW police received over 20,000 reports of shoplifting with most going unpunished.

Port Douglas has not escaped the practice and Coles has been targeted.

Since installations started, self-checkouts have become abundant across the state with supermarkets cutting staff in a bid to save money.

However, due to the unsupervised nature of the system, it has enabled thousands of Australians to find loopholes at the checkouts, resulting in a rise in shoplifting.

Superintendent Murray Chapman said that police would be working alongside supermarkets to assist in spotting shoppers abusing the self-checkout.

“I believe some people may think it’s opportunistic and they can get away with it. The message has to be, if you shoplift you will get caught,” Supt Chapman said.

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

The CEO of the National Retails Association, Dominique Lamb, said theft is costing the retail industry $4.5 billion a year.