The moves offers customers the convenience of buying milk without having to leave their cars and one local franchise owner said he planned to also sell bread in a similar fashion in the future, The Gold Coast Bulletin reports.
"We started selling the milk about six weeks ago to see what sort of response we would get from our customers," McDonalds franchise owner Joe Condon said.
"We don't want to take the focus away from food, but thought it was another convenience item to offer.
"The response has been great and I think it will be something that becomes permanent and will eventually be rolled out nation-wide."
Mr Condon said the move allows the fast-food giants to test the market and at this stage milk was the only grocery item on the menu.
"It is just milk for now, as it is easy to store and sell," he said.
"Bread is another convenience item, but it will take more space and care, so we will see how we go."
The milk being sold at McDonalds is local brand Norco full cream or Norco light for $3.50.