The reality of the current debate is that silence or ambivalence will be taken as a statement to get rid of the Single Desk, Queensland Nationals Senator Barnaby Joyce has warned.

"It is peculiar that groups, who say they represent rural groups, and have strident statements on everything from lobbying to sell Telstra or on the passage of Mergers and Acquisitions laws to assist big business become enormous, do not have a position on the Single Desk.

"There is no fence to sit on. Either you advocate the retention of the Single Desk, anything else is advocating its dismantling.

"That is the reality of the politics on this issue. It is of utmost importance that if a group believes they cannot deliver a position on the Single Desk that they advise their members to make their own way on the issue should those members wish to protect the Single Desk.

"The loss of the Single Desk will be the loss of Australia's major marketing advantage to its major competitors.

"The purchase of 60% of the world's wheat is through a single desk, you cannot have a pool with the buyer of last resort without a power of veto.

"Our major competitors the US and EU would do anything to get rid of our Single Desk. They will get their way over our growers if there is not an active campaign to stop them in Australia now," Senator Joyce said.