President Donald Trump has taken a sharp U-turn on previous comments made about Canada's strategic partnership with China.

US Commerce Secretary Howard Lutnick dismissed as “political noise” the moves in recent days by Canada’s Prime Minister Mark Carney to strengthen trade relations with China, and raised the risk of that maneuver seeping into talks over a revamped North American trade accord later this year.

Diplomatic tensions rise as Donald Trump alleges Canadian opposition to US missile defence over Greenland, criticises trade with China, and Canadian leaders respond.

Canada and China have reached a preliminary agreement to remove all tariffs from canola meal and peas. Tariffs on canola seed are expected to be reduced to 15 per cent.