Wesfarmers is conducting an internal investigation into the supermarket chain Coles' treatment of its suppliers after the corporate watchdog raised concerns about predatory behaviour in the industry.
Coles and Woolworths may have misused their market power by imposing unfair penalties on suppliers, demanding additional payments and discriminating against them in favour of their private label brands.
The comment was made by Australian Competition and Consumer Commission (ACCC) chairman Rod Sims to the Senate economics estimates committee in Canberra on Wednesday.
The ACCC was also concerned about the supermarket giants' shopper dockets offering petrol discounts, as they could not be matched by other fuel retailers.
Coles is wholly owned by Wesfarmers.
Wesfarmers managing director Richard Goyder told the company's results briefing on Thursday that it had been conducting its own inquiries into the matter and would co-operate with any investigations by the competition watchdog.
"We've got internal processes to ensure we behave in a responsible and ethical way," he said.
"If there's evidence that these things apply to us, we'll obviously co-operate with the ACCC through any investigation and deal with any issues that come up appropriately.
"We're doing our own investigation and obviously the ACCC is doing one and we'll let it all unfold."
Mr Goyder said he would not support increasing the amount of red tape to deal with the issue.
"The last thing that we need in this country with productivity challenges is creating more layers of bureaucracy when they're not required," he said.
"The ACCC has more than enough powers to deal with any particular issues around how we or anyone else may behave, including how our suppliers might behave."
Mr Goyder said Wesfarmers was already part of a group of suppliers, retailers and government agencies called the Retailers' Suppliers Round Table that was dealing with industry concerns.
The ACCC began investigating during 2012 whether supermarket voucher deals would affect consumers in the long term.
Mr Sims said he hoped the investigation would be completed by mid 2013.
