President Reagan is praising Canadian Prime Minister Brian Mulroney at a time when Mulroney is encountering opposition to a sweeping U.S.-Canadian free-trade pact.

At the same time, Reagan had kind words Monday for a U.S. Congress that often has come in for his criticism, saying lawmakers had put the agreement "on a fast track" - just as he asked.The setting for the president's remarks was a Roosevelt Room ceremony at which Reagan signed letters transmitting to Congress legislation to implement the agreement.

"Throughout North American history, whenever and wherever trade barriers have been lowered, we've seen our economies bloom like mountain meadows after a spring rain," the president said.

"This agreement is a sun rising on a new morning of economic vitality," he said. "It will save U.S. consumers up to $3 billion a year. It will help keep the North American economy growing for a generation to come."

On Jan. 2, Reagan and Mulroney signed an agreement that provides for the elimination of all tariffs in the two countries' $150 billion-a-year trade. It also would reduce many non-tariff barriers, liberalize investment practices and provide new rules covering cross-border trade in services.

Reagan did not allude to the political situation in Canada, where Mulroney's Liberal Party opposition has threatened to stall legislation implementing the accord there until Mulroney calls new elections.

But Reagan quoted his Canadian counterpart as saying, "The choice couldn't be more clear-cut - the voices of the past against a vision of the future."

"I asked the Congress to put this on a fast track, which it did, and then some," he said. (Auto racing driver) Rick Mears couldn't have driven it any faster, which shows what we can do when Democrats and Republicans work together."

The accord ran into trouble last week in Canada when the opposition Liberal Party vowed to block ratification until Mulroney calls a general election.