Agriculture Minister David Littleproud has revealed he has commercial shares in Woolworths, after he urged Australians to boycott Coles and “the big German” Aldi over cut-price $1 milk.

But Mr Littleproud has defended his modest ownership as irrelevant to his campaign for a fairer deal for Australia’s farmers.

The issue erupted on Twitter on Tuesday, after he was challenged by a voter to come clean on his share ownership.

“I have 25 shares in Woolworths worth about $700. A simple google will reveal I’ve also bashed Woolworths, CBA, ANZ, and Telstra and I’ve got shares in them too. So long as Coles and Aldi refuse to be fair to farmers they can expect more heat from me,” Mr Littleproud said.

I have 25 shares in Woolworths worth about $700. A simple google will reveal I’ve also bashed Woolworths, CBA, ANZ, and Telstra and I’ve got shares in them too. So long as Coles and Aldi refuse to be fair to farmers they can expect more heat from me

— David Littleproud MP (@D_LittleproudMP) February 19, 2019

Earlier Mr Littleproud had savaged the supermarkets for ripping off farmers by selling $1 milk and urged families to boycott the big supermarkets’ cut-price milk until they follow Woolworths’ “leadership” and raise their prices. 

Woolworths has stopped selling $1-a-litre a milk as of Tuesday, implementing a 10-cent-a-litre price rise. The increase will go directly to drought-hit farmers.

Mr Littleproud said dairy famers were begging the two remaining big supermarkets to stop flogging cheap milk. 

“I say to every Australian: They can also vote with their feet. They can stick it right up Coles and the big German and not go anywhere near their shops, and go and support retailers that support the dairy industry,” he said.

“We won’t have an industry unless they show some leadership.”

Mr Littleproud said Coles “needed to be called out on publicity stunts and rubbish claims” such as encouraging consumers to donate to farmers instead of paying a fair price.

“Publicity stunts like asking shoppers to donate at the counter to help struggling farmers are just a smokescreen to hide the fact they pay bugger all for milk,” he said. 

“The farmers wouldn’t need donations from the public if Coles and Aldi paid fair prices.”

Accusing Aldi of “hiding under the stairs”, after it failed to follow Woolworths, Mr Littleproud also said he attacked Coles’ statement that it wanted to work with the farming industry to build a more sustainable future.

“Coles has said this since August, so it’s time to put up or shut up,” he said.

Act like a decent corporate citizen instead of pretending to. I encourage farmers to get out there in their local paper, radio or TV station and call this arrogant behaviour out. 

“The Australian public deserve the truth. I also encourage Wesfarmers shareholders to contact Coles and let them know they don’t want to continue this approach of hurting farmers in private whilst handing them bouquets and small donations in public when the cameras are on.

“It’s the beginning of the end, we hope, of the $1 milk.”

On Tuesday, Coles said it had committed $16 million in the past six months to support the farming sector, and would liaise with the industry and the Australian Competition and Consumer Commission on future initiatives.

“Coles also knows that many customers in Australia face cost-of-living pressures and doesn’t want them to be disadvantaged through price increases,” a spokesman said.

“We also note that the ACCC has previously examined the Australian dairy industry and concluded that house-brand milk pricing does not negatively impact farm-gate milk prices.”

Aldi said delivering cut-price groceries was a core part of its brand and it had no plans to dump cheap milk.

“Aldi can best support the long-term sustainability of the dairy industry by accepting price increases from milk processors that reflect difficult market conditions, thereby facilitating its milk processors to pay sustainable prices to dairy farmers,” managing director Oliver Bongardt said.