The Australian Competition and Consumer Commission (ACCC) is seeking evidence from supplies of supermarket giants Coles and Woolworths to nail the two grocers on unfair competition charges.

Rod Sims, chairman of the ACCC, said on Tuesday that it is the regulator's priority to uncover possible abuses of market power after it received new allegations of unfair competition by Coles and Woolies in the past six months.

Among the complaints made by suppliers and farmers of the two supermarkets are their price war which has squeezed their profit margin and a preference for home-brand products. Mr Sims promised to protect whistleblowers from a possible repercussion from the supermarkets.

"They can come and talk to us confidentially and if we can get a number of people talking to us confidentially and we can build up a picture then we can take action in a general sense rather than doing it in a way that exposes that individual," Mr Sims said.

Coles and Woolworths started their price war in 2011 by reducing the prices of milk, bread and detergent. In February, the price war spread to fresh vegetables and fruit. Both grocers also ventured into the area of sustainable fresh fish, while Woolworths launched its virtual supermarket this week which allows shoppers to purchase from a list of 120 items using their mobile phone with Woolies apps.

The ACCC had made in 2008 an investigation into retail prices but came out with the finding that retail prices went up while farm-gate prices remained at the current levels or went down.

Mr Sims, who outlined the ACCC priorities for 2012 in a speech at the Australia-Israel Chamber of Commerce meeting in Melbourne, said the agency would also focus on fuel suppliers and the telecommunications industry.

RELATED STORIES