The senior Nationals frontbencher also took a swipe at Coles for ending a temporary 10-cent levy on three-litre home brand milk, which saw $3.9 million flow to more than 600 producers.

"Coles announced a drought levy and it'd be disgraceful to withdraw it a few months later while the drought intensifies," the minister said.

"The drought did not end on December 31 and neither should the levy."

Mr Littleproud urged Coles customers to vote with their feet and shop somewhere else, but reserved his most savage offensive for the "big German".

"Aldi is worse. Aldi has done bugger all for farmers in drought," the minister said.

"Coles and Aldi both need to show they give a damn about Aussie farmers."

Earlier in the week, Coles said the money would support to dairy farmers to assist with feed and water costs for their cattle, farm improvements and help with household expenses.

Aldi has previously defended itself, saying the company was working directly with suppliers to ease pressure on farmers by accepting price increases.

Mr Littleproud accused Coles of introducing a drought level on milk only to follow major rival Woolworths' lead.

"Its half-hearted attempt did not include a proper payment process to make sure the farmers supplying the milk were paid per litre they supplied," he said.

"Woolworths isn't perfect either but at least their levy is going to the farmers who supplied the milk and they show no sign of pulling it.

"I encourage consumers to shop with their feet for the good of Aussie farmers."

Australian Associated Press