The consumer watchdog has vowed it will “forensically” examine possible price gouging at the checkout as part of its 12-month inquiry into the supermarket industry.

The inquiry follows accusations major supermarkets had been significantly increasing prices on fresh produce compared to what they were paying farmers and suppliers for products such as fruit, vegetables and meat.

Australian Competition and Consumer Commission deputy chair Mick Keogh said the industry had rapidly changed since its last inquiry into the sector in 2008.

“The focus will be on the extent to which there’s competition between supermarkets and the margins that are gained on the way through the supply chains,” he said.

“This will give us the opportunity to quite forensically look at those pieces of information and get to the bottom of what is going on there.”

Mr Keogh said the surge of online retailing in supermarkets and consolidation in supply chains will also come under the microscope as part of the inquiry.

He also said the duopoly of Coles and Woolworths would be a significant focus.

“There’s been significant growth of the two majors, and it still remains the fact that Australia has got one of the most concentrated supermarket sectors in the world.

“Coles, Woolies just became too strong, too big, too powerful and they’ve just basically pushed out anyone else who tried to get in their way.”

Mr Keogh said he was confident of the ACCC inquiry leading to results in the industry.

Woolworths chief executive Brad Banducci said the company would assist the ACCC with its inquiry and acknowledged pressures of the food shop on household budgets.

In a statement, Coles said it looked forward to illustrating to the inquiry how it provided value to customers and its positive relationships with suppliers.

The ACCC probe comes as well as a review of the grocery code of conduct, being overseen by former Labor minister Craig Emerson, along with a Senate inquiry.