Carney has been stressing the need to build stronger international ties as his government looks to reduce Canada's reliance on the United States for trade.
Canada Post spokeswoman Lisa Liu said in a statement that no new mail will be accepted during the labour disruption.
Canola oil exports moving through the port were up 72 per cent to 700,000 metric tonnes as cargoes were able to move to markets other than China and the United States.
Carney had been scheduled to meet with the Danish prime minister, but that meeting was cancelled.
In the second quarter of this year, Canada Post recorded a loss before tax of $407 million — the Crown corporation's largest loss before tax in a single quarter. Canada Post reported a profit of $46 million in the same period a year earlier.
Real gross domestic product grew 0.2 per cent in July, marking the first signs of growth in four months. Real GDP declined 1.6 per cent on an annualized basis in the second quarter.