Someone has dumped 100 bushels of wheat at Tory candidate Larry Maguire's Brandon campaign office in an apparent protest.

The bushels showed up Monday morning as Canada signed the Trans-Pacific Partnership, a 12-nation trade agreement.

"Obviously, we just signed the largest trade agreement in Canadian history – one that involves 40 per cent of the world's trade, and we cannot be left out of that. It's extremely important," said Maguire. "It's exciting for southwest Manitoba."

Farmers have raised concerns about the deal, which will open up international trade.

Manitoba will now have duty-free market access to agricultural and agri-food products such as canola, feed wheat, frozen French fries, dried peas and beans, feed barley and honey. It will also enhance market access for pork, wheat, barley and malt.

Some farmers are worried that means a loss for them. Dairy producers in particular are concerned.

Farmers worry the deal will open the market to American dairy, which they believe could close family farms across the country.

The Conservative government has already opened up trade for wheat when it privatised the Canadian Wheat Board.

Maguire, who is running in Brandon-Souris, touted the benefits of the TPP on Monday and said he is taking the unusual protest in stride, though.

"We're saying somebody dropped off a donation," he said. "You can't make everybody happy every day, and this is certainly a situation where it's a win-win. And it's not just for the farmers in this region. This is important to every citizen that's living in Brandon and all over smaller communities as well because it really enhances the economy.

"On the other side of it, if we hadn't been able to do this and let the U.S. and Japan sign their own agreement on hogs, our industry would have been in jeopardy."

Maguire donated the grain to the Canadian Foodgrains Bank Monday afternoon after a local grain farmer offered the help of his truck.