Australian federal treasurer Peter Costello is to question fastfood company McDonald's about its decision to source some of its potatoes offshore following a meeting with Tasmanian farmers, according to the Australian Associated Press.

Farmer Richard Bovill, coordinator of the state's Fair Dinkum Food Campaign, said the treasurer "listened intently" to the farmers' concerns and undertook to question the fast food chain on its decision-making process.

Tasmanian potato farmers were floored last month when processing company Simplot lost half of its McDonald's French fries contract, a loss of about A$50m (US$38m) to the state's economy.

The growers previously supplied all French fries to McDonald's Australian outlets but will now share the contract with McCain Foods, which will source some of its potatoes from New Zealand.

Bovill said he was confident the government would act to support the food industry.

"I sense in the treasurer's attention that he's concerned about Australian communities and the wellbeing of Australian communities and people, and that he does place a high importance on their wellbeing as opposed to the sheer greed of some large companies," he said.

"We actually have to get into the psyche of these companies that this is where you derive your income from."