The federal agriculture minister has savaged Coles and Aldi for keeping their cut-price milk lines and has urged customers to boycott them.
David Littleproud has accused Coles of "pretending" to be a decent corporate citizen, and Aldi of "hiding under the stairs", after they failed to follow Woolworths and stop selling milk at $1 a litre.
He said dairy farmers struggling with drought need an end to Australia's "$1 milk disaster", a price war that began eight years ago and has been blamed for sending some farmers to the wall.
"Publicity stunts like (Coles) asking shoppers to donate at the counter to help struggling farmers are just a smokescreen to hide the fact they pay bugger all for milk," Mr Littleproud said.
"The farmers wouldn't need donations from the public if Coles and Aldi paid fair prices. The big German needs to come out from hiding under the stairs and face the Australian public."
On Tuesday, Coles said it would not axe it's $1-a-litre Coles-branded milk, citing cost of living pressures on customers.
It said it would look for other ways to help farmers, including collecting customer donations and matching them dollar for dollar from next week.
It also pointed out it had committed $16 million over the past six months to support diary farmers, and promised to continue liaising with the industry and the Australian Competition and Consumer Commission (ACCC) on future initiatives.
But the minister said Coles had been saying that since August.
"So now it's time to put up or shut up. Act like a decent corporate citizen instead of just pretending to," he said.
Aldi has so far failed to respond to AAP's requests for comment about whether it would change its milk pricing policy.
Mr Littleproud said Australians should send a message with their wallets, and switch their business away form Coles and Aldi.
Woolworths stopped selling its home-brand milk at $1 a litre on Tuesday, upping the price by 10 cents with the extra money to go back to farmers.
