Customers will pay more for milk at Coles and Woolworths stores with the levy to be passed on to dairy farmers gripped by drought.
The supermarket giants have announced milk sold under their brands will cost an extra 10 cents a litre from Thursday.
It comes amid a myriad of campaigns raising funds for farmers struggling against bone dry conditions, and follows a Queensland Dairyfarmers' Organisation petition calling on Australians to shell out.
Coles will increase the price of its 3-litre branded milk from $3 to $3.30 until the end of the year.
Woolworths will do the same until mid-October, when it introduces a temporary range of drought relief milk at $1.10 per litre in Queensland, NSW, ACT and Victoria, with funds going to farmers in those states.
The retailer says money raised will go to its supplier, Parmalat, which will then distribute it on a monthly basis among the farmers it works with.
Federal Agriculture Minister David Littleproud said he'd been assured all of the money would get to the farm gate.
"I'm going to hold them to account, don't worry," Mr Littleproud told ABC radio.
"There's still more to be done, I'm not running away from it, but it's a good first step."