Farmers could get a mandated minimum price for milk, with Labor promising to investigate the move if the party wins the next federal election.
Labor wants the consumer watchdog to test how a minimum farm gate milk price would work to protect the dairy industry.
Federal Agriculture Minister David Littleproud on Tuesday 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 the price war that began eight years ago had been a disaster for farmers.
The minister also hit out at Coles for saying it would run another donations drive to help struggling farmers, calling it a publicity stunt and a smokescreen.
Now Labor wants to regulate to fix the problem.
"It is not acceptable for our farmers to be paid less than the cost of producing their milk," Labor agriculture spokesman Joel Fitzgibbon said on Wednesday.
"If a floor price is needed to end this crisis, that's what Labor will deliver."
Labor is also promising to establish a mandatory dairy code of conduct to ensure the market is functioning fairly for all participants.
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.
Coles said it would not axe its $1-a-litre Coles-branded milk, citing cost of living pressures on customers.
Aldi said low prices were a core promise to its customers, and it did not support retailer-lead initiatives seeking to bypass the normal supply chain.
