Prime Minister Stephen Harper said Thursday he's disappointed with a court ruling that the Conservative government overstepped its authority in trying to end the barley monopoly through a cabinet order.

"We're obviously disappointed with the court decision," Harper said in Charlottetown.

"We should make it clear that does not change the determination of the government of Canada to see a dual market for Canadian farmers. Canadian farmers have spoken very clearly that they want to see this barley market open."

Harper referred to changes in barley prices that happened the morning the decision went out. Cash prices for western barley dropped Wednesday morning by about 70 cents a bushel, while futures prices were down $7.50 a tonne.

"When the barley market appeared to be coming open, prices went up and now that it appears that it might not be open, prices are going back down," the prime minister said.

The message for the wheat board is clear on the subject of dual marketing, Harper said.

"The message is, farmers want it, prices will go up; farmers want high prices and the wheat board is supposed to get high prices for farmers."

In a ruling issued Tuesday, Federal Court Judge Dolores Hansen said the government overstepped its authority earlier this year when it passed a new regulation that would have allowed farmers to sell their barley independent of the Canadian Wheat Board starting Aug. 1.

The ruling means that for the time being, government has been dealt a setback and the Winnipeg-based grain agency retains its monopoly on the marketing of some barley.

Wheat board chairman Ken Ritter said Wednesday the drop in prices was a "blip" and prices would come back up.

The future of grain marketing and the wheat board's role in it is a subject that has deeply divided Prairie farmers.

Some say they want to sell their own grain to take advantage of higher spot prices. Others say they're already getting the best prices through the wheat board and are worried dual marketing will be the beginning of the end for the board.

Federal Agriculture Minister Chuck Strahl said the government is looking at its options to bring marketing choice to barley farmers, including going through Parliament.