Coles has again rejected calls for the Federal Government to appoint a supermarket ombudsman.

The Food and Grocery Council says Coles' decision this week to offer heavy discounts on fresh produce shows an ombudsman is needed to enforce a fair trading code of conduct.

Coles launched a flurry of ads spruiking discounts on fresh produce.

A range of items have been discounted by as much as 50 per cent.

The latest round of cuts comes on top of Coles and Woolworths scrambling to undercut each other on items such as bread and milk.

Coles chief executive Ian McLeod says a supermarket ombudsman is unnecessary.

"I think the ACCC (Australian Competition and Consumer Commission) have got very extensive powers and if they've got some real concerns that can be backed up with empirical support, they will investigate extremely thoroughly. That's my experience," he said.

"So I don't think that's necessary.

"I mean, arguably, I could be calling for a supplier ombudsman.

"There are a number of key suppliers that operate in Australia that have substantially more market share in theirs than we have in ours."

Grower concerns

Farmers' groups have been renewing warnings that the supermarket price war risks driving growers out of business.

And shoppers have been warned that savings on some items may be clawed back by the supermarkets on other lines.

Coles spokesman Jon Church said that the discounts represented a win for both shoppers and producers.

"The farmers that supply Coles with fresh milk didn't receive less for that milk, we in fact paid our processors more so that when we cut the retail price, farmers weren't disadvantaged," he said.

"The Senate inquiry found that that price cut was pro-competitive and beneficial to consumers, and they also found that dairy farmers weren't disadvantaged by the cut as well.

"So milk was a good move for customers, didn't impact on farmers, and this fresh produce price cut will be the same."