WINNIPEG - The Manitoba government has launched a battle with Ottawa, taking out ads and starting an online petition opposing federal plans for the Canadian Wheat Board.

Stripping the board of its decades-old monopoly on western grain sales will "rob farmers" and lead to hundreds of job losses, Manitoba's NDP government says in a series newspaper and radio ads that will cost provincial taxpayers $180,000.

Premier Greg Selinger, who normally prefers to negotiate quietly with the federal government, warned that opening grain sales to competition would be disastrous.

Producers "will lose their competitive advantage in terms of shipping grain," Selinger said Monday.

"We want (the federal government) to listen to producers and farmers and give them a say in what the future of the wheat board should be."

Prairie farmers have had no choice but to export their grain through the board since 1943. The board was set up in response to plummeting prices, and is the last of its kind in the world.

Many farmers have demanded the freedom to sell their grain independently, as their counterparts in Eastern Canada already do, and the federal Conservatives have promised to allow that.

Agriculture Minister Gerry Ritz has said that if the wheat board really is the best option for farmers, many will continue to use it and it will survive. But he has consistently said that farmers should have the right to seek better prices elsewhere.

Now that the Conservatives have a majority government, legislation to end the wheat board monopoly is expected within months.

Ritz accused Manitoba of ignoring the will of most farmers.

"Our government has always put farmers first, which is why western Canadians gave this government a strong mandate and now they expect us to deliver on our commitments," Ritz said Monday in a written statement.

"It's disappointing but not surprising that the Manitoba government would be against an open and competitive market that would attract investment, encourage innovation and create value-added jobs.

"The CWB and the Manitoba government should work constructively to let every farmer decide how they market their grain instead of engaging in gratuitous fear mongering."

But Selinger and other wheat board supporters say the board cannot survive in an open market and farmers will end up competing with each other for sales instead of acting as one.

The Saskatchewan and Alberta governments support the federal government's move. Manitoba has long opposed it, and has more at stake -- the wheat board has 400 headquarters jobs in Winnipeg and is the biggest customer of the Port of Churchill in northern Manitoba.

Selinger wants the federal government to put the matter to a farmer plebiscite before making any changes.

"We think that ability, for the producers to have a say in how the wheat board operates on their behalf, is fundamental," Selinger said.

The wheat board is a farmer-controlled organization, and a majority of its board members have been elected on a campaign to preserve the monopoly.