A Welsh livestock group that has fallen out with Vion Food Group over direct payments to farmers is set to have its grievances aired in Westminster next week.

Graig Producers said last week it had suspended trading with Vion because the processor had told farmers it would start paying them directly and no longer through Graig. This represented a major shift in the balance of power and would make it more difficult for smaller farms to compete, Graig said.

Graig’s concerns have already been aired in the Welsh Assembly, where Wales’s deputy minister was said to be “very concerned” and about to make a statement on Graig’s situation.

Roger Williams, MP for Brecon and Radnorshire, is now proposing to raise the issue in the House of Commons next week, with questions also to be raised in the Lords.

Vion said it had introduced direct payments to increase supply chaintransparency. “The issue with Graig Producers is isolated and not a move to bypass co-operative groups,” a spokesman said. “Vion continues to maintain a positive, constructive commercial relationship with other farmer marketing groups.”