COLES is cracking down on sticky-fingered customers as self-service tills prompt a rise in shoplifting.

The supermarket giant said the self-service check-outs had proved a hit with customers, typically being used for about half of all transactions in the 600 stores where the tills were offered.

But the group said it was stepping up its focus on the small percentage of dishonest shoppers who exploited the unsupervised tills.

"The vast majority of our customers are very honest, but we are putting in place processes that keep a handle on theft," said Richard Goyder, managing director of Coles' parent company Wesfarmers.

Mr Goyder said the specific action would be kept under wraps to avoid alerting would-be thieves to its techniques, but said Coles was drawing on international retail experience to develop its battle plan.

"It's about the way we lay the tills out and the way we monitor them," Mr Goyder said.

"Retailers around the world are all doing this."

It is believed the majority of theft from the self-service tills centres around items being deliberately scanned incorrectly.

But Coles said despite the risk of theft, the self-service tills were a popular feature with more set to be rolled out across the network.

"It's not uncommon to see people line up for the self-service check-outs, even when manned tills are available," Wesfarmers finance director Terry Bowen said.

"In other words, customers really like them."

It came as Coles yesterday reported a 4.9 per cent boost in total sales to $8.9 billion for the three months to September.

Mr Goyder also said retailers could be looking forward to a better Christmas this year, with rising house prices, low interest rates, and more positive overseas news expected to prompt cautious consumers to open their wallets.