The group Friends of the Canadian Wheat Board filed the lawsuit in 2012 over legislation that removed the marketing agency's monopoly on western wheat and barley sales.
Last month, the Federal Court of Appeal ruled against the group's challenge of a lower-court decision that struck down parts of a class-action lawsuit that alleges expropriation and interference with economic relations.
Stewart Wells, a spokesman for the group, says it will seek leave to appeal to the Supreme Court.
He says the Federal Court of Appeal ruling does not properly address what he calls the injustice of Ottawa seizing and disposing of wheat board assets paid for by farmers.
Ritz says the legislation delivered on the government's promise to give western Canadian grain farmers the marketing freedom they wanted and deserved.
"While the overwhelming majority of farmers look to the future, it is unfortunate that a small few remain stuck in the past," Ritz said in an email Wednesday.
"Court after court continues to uphold the rights of farmers to have marketing freedom. The new CWB is increasing its capacity to remain a vibrant marketing option for farmers."
The federal government plans to privatize the wheat board before August 2017.
In part of its Oct. 15 ruling, the Federal Court of Appeal did uphold the right of the Friends of the Canadian Wheat Board to sue Ottawa over wheat board money that the group claims was misallocated in the 2011-12 crop year.
Statements of claim contain allegations that have not been proven in court.
Ritz said the federal government will continue to work with "forward- thinking producers" to build a stronger future for Canadian agriculture.