Tasmanian dairy farmers are threatening a walkout from the state's peak farming body after the association appeared to back National Foods' latest price offer.

Farmer Phil Beattie says the Farmers and Graziers Association went behind dairy farmers' backs, meeting National Foods executives in Melbourne and releasing a statement recommending farmers accept the diary giant''s latest price offer.

He says no farmers were consulted and has warned diary farmers could resign from the group.

"They would lose a huge amount of income from levies, over a $100,000 a year," he said.

The TFGA will hold a board meeting today.

Mr Beattie says he wants the TFGA's Chief Executive Officer Chris Oldfield to come clean over why secret meetings were held with National Foods.

Mr Oldfield has been contacted for comment.