The Conservative government tabled long-promised legislation on Tuesday to end the Canadian Wheat Board's 60-year monopoly on western wheat and barley.

"An open market will increase the number of buyers bidding on our wheat and barley," Agriculture Minister Gerry Ritz said on an Ontario farm Tuesday.

"Unlike what some people may claim, the sky will not fall in an open market. Instead, the sky will be the limit."

The move came under the fire of opposition critics who said privatizing the wheat board will be a bad deal for farmers.

"There is simply no case for abolishing the Canadian Wheat Board. We've been asking them, ‘If you (have) some evidence that proves that Prairie farmers will be better off, show us and we'll back off," NDP MP Pat Martin told CTV's Power Play.

"The Canadian Wheat Board is the largest and most successful grain marketing company in the world. It's a great Canadian institution."

Unlike elsewhere in the country, western farmers must sell their wheat and barley through the board. It was founded in the 1940s when farmers banded together to get negotiate better prices for themselves. The Wheat Board is governed by federal law and run by a board of governors, mostly voted in by farmers.

Some farmers say they want the right to buy or sell their wheat or barley to whomever they choose and negotiate their own price. But others say without the wheat board's monopoly, farmers will end up competing with each other and lowering prices.

A group called Friends of the Canadian Wheat Board has already taken the issue to federal court and called for a judicial review of the government's plan. The Wheat Board's leadership have said they will take the issue to court.

Under current law, any changes to the Canadian Wheat Board have to be approved by producers.

The new legislation does away with the requirement for a producer plebiscite and opens sales on Aug. 1 for next year's crop.

The bill also changes the Wheat Board's board of directors as elected members will be removed when the bill becomes law, expected in early 2012.

Ritz said farmers already own some of the infrastructure to get their crops to market and they will have options on how to market their product.

"There's nothing stopping farmers from forming a co-operative, from pooling their resources so that they have economy of scale," he said on Power Play.

Manitoba's NDP government opposes the plan. As the Wheat Board is based in Winnipeg it has the most to lose, with hundreds of jobs located there.

U.S. ambassador to Canada David Jacobson weighed in tentatively on the legislation Tuesday.

"That's an issue for the Canadian government to decide. The fact of the matter is that we believe in free trade and the more open the markets are on both sides of the border, probably the better off the people on both sides of the border are," he told Power Play.