Canada's international trade minister is pushing Washington to ease tough labelling provisions that he says are hurting Canadian businesses.

Stockwell Day gave notice on Monday to U.S. Trade Representative Ron Kirk that Canada is moving ahead with a World Trade Organization process to object to the country-of-origin labelling requirements.

The rules were introduced in February, and require U.S. producers to indicate the country of origin of food products that include meat, fruits, vegetables and some nuts.

Day told CTV's Canada AM on Tuesday that Ottawa asked for clarification on the rules some time ago, and received it, but the details are still murky.

"They've left a whole lot of questions under something called 'voluntary compliance,'" Day said.

"The rules are so unclear that production facilities in the United States are actually starting to turn back Canadian products, saying it's just too confusing to try and meet these labelling provisions."

Day said the products are often raised, fed and processed in three different places, making the labelling complicated and cumbersome under the new rules.

Canadian beef and pork exports to the U.S. have dropped dramatically in recent months, and producers are blaming the country-of-origin labelling rules that allow American consumers to avoid non-U.S. products.

Under the WTO consultation, U.S. trade representatives are required to enter into negotiations on the issue with their Canadian counterparts for 60 days.

"Hopefully during that period we can get this worked out," Day said.

Another issue on the table is linked to the controversial 'Buy American' provisions of the U.S. stimulus bill.

Day said he spoke to Kirk about reports that Canadian companies aren't being allowed to bid on municipal or state infrastructure projects in the U.S., due to the Obama administration's Water Quality Investment Act of 2009.

Canadian businesses, as well as U.S. businesses that are owned by Canadians, are suffering from the provision, Day said.