Prime Minister Justin Trudeau will not join his North American counterparts in Washington, D.C., this week to celebrate the coming into force of the three countries' renegotiated trade pact.

"While there were recent discussions about the possible participation of Canada, the prime minister will be in Ottawa this week for scheduled cabinet meetings and the long-planned sitting of Parliament," Chantal Gagnon, a spokesperson for the Prime Minister's Office, said in a statement.

The updated NAFTA deal, called CUSMA in Canada and USMCA in the United States, came into force on July 1. U.S. President Donald Trump is hosting Mexican President Andrés Manuel López Obrador in Washington for a bilateral meeting on Wednesday.

The prime minister did speak to López Obrador by phone today to discuss the trade pact and expressed regret for not being able to join him and Trump in Washington D.C.

"The two leaders discussed the significant efforts made by each country to fight the COVID-19 pandemic and looked forward to their next opportunity to meet in person," said a readout of the call.

Trudeau is attending a virtual cabinet retreat today and tomorrow and Finance Minister Bill Morneau is delivering what he has called a "fiscal snapshot" on Wednesday.

Asked last week whether he would attend the Washington meeting, Trudeau said that COVID-19 posed an obvious concern, given that Canadian public health rules would mean he would have to quarantine for two weeks upon his return.

But Trudeau also mentioned a nagging trade issue with the United States.

"We're obviously concerned about the proposed issue of tariffs on aluminum and steel that the Americans have floated recently," he said, referring to Trump's statement last month that he might look at reintroducing tariffs on Canadian aluminum.

U.S. tariffs on steel and aluminum in 2018 led to a nearly year-long trade spat, with Canada levying retaliatory tariffs on U.S. goods until a deal to lift them was reached in May, 2019.

The NAFTA file had been in Chrystia Freeland's hands since Trump first demanded the trade pact be reopened. ​As foreign affairs minister, ​Freeland spent months shuttling back and forth between Ottawa and Washington in 2018 and 2019, and continued to oversee the deal even after being named deputy prime minister after the election last October.

A June 29 Order in Council passed that responsibility to International Trade Minister Mary Ng, as outlined in the legislation to implement the deal.