Claiming a clear national mandate for the free- trade agreement with the United States, Prime Minister Brian Mulroney said he will proceed to quick enactment.

He announced Tuesday, the day after leading his Progressive Conservative Party to its second consecutive majority government, that Parliament will be called back into session the week of Dec. 12.The U.S. Congress has passed legislation needed for the trade pact to start taking effect Jan. 1 as scheduled, but it still needs final Canadian parliamentary approval.

"The Canadian people have given us a clear mandate to implement the free-trade agreement. We intend to do so," the prime minister said at a nationally televised news conference from his hometown of Baie-Comeau, Quebec.

His party won 170 seats in the 295-member House of Commons in a campaign completely dominated by the free trade issue and marked by intense opposition from Liberal Party leader John Turner.

The Liberals won 82 seats, and the socialist New Democratic Party, which also opposed the agreement, will have 43 seats in the new House.

President Reagan, who signed the agreement with Mulroney on Jan. 2, congratulated the prime minister in a telephone call Tuesday from his ranch in Santa Barbara, Calif.

Mulroney also said he spoke with President-elect George Bush and was willing to meet with him before the U.S. inauguration.

The Canadian dollar jumped in value against the U.S. dollar to more than 83 cents on the strength of the Conservative victory.

The trade pact phases out all remaining tariffs between the two countries, already each other's largest trading partners, over a 10-year period. It also dismantles many investment barriers; frees up trade in energy and services, and creates Canadian-U.S. panels to settle disputes (see Utah story on this page).