A desperate plea by Victorian dairy farmers to buy branded milk has been heard, with shoppers taking to social media to share their photos of empty supermarket shelves.

Dairy giants Murray Goulburn and Fonterra have dropped the price of milk solids to below the cost of production for many farmers, leaving some out of pocket by more than $3,500 a month.

The crisis has sparked a broader discussion about the state of Australia's dairy industry, with farmers urging consumers to avoid discounted milk.

The appeal has since gone viral on the "Dairy Farmers Need Your Help please" Facebook page, with one image of empty milk shelves in Camperdown, in Victoria's south-west, receiving more than 20,000 shares and 18,000 likes in support.

"The cheap stuff has barely been touched," former milker and Cobden local Jasmine Mackay wrote in the post.

"The same thing is happening all over, all the home brand milk shelves are full," wrote another.

Similar images have since been shared of supermarket shelves across Victoria, including Echuca in central Victoria and Leongatha in Gippsland.

The Australian Securities and Investment Commission and the Australian Consumer and Competition Commission have since confirmed they are investigating the actions of Murray Goulburn and Fonterra, while the Federal Government has vowed to extend assistance programs to struggling farmers.

Meanwhile, Deputy Prime Minister Barnaby Joyce has called on other supermarket chains to follow Coles and return more money to dairy farmers from milk sales.

Coles has announced it would develop a new milk brand which would return 20 cents a litre to a fighting fund aimed at helping dairy farmers facing devastating cuts in their payments from processors.

The Agriculture Minister acknowledged the big supermarket chains had followed Coles in the race to the bottom with $1 a litre retail sales.