Vice President George Bush said today that despite occasional trade spats and lapses into protectionism, the United States is anxious to continue comprehensive free-trade talks with Canada.

"I am convinced that both the U.S. and Canada will benefit from freer and increased trade, and I emphasized in my meeting with the prime minister Brian Mulroney the strong commitment of our administration to making the talks on freer trade bear fruit for both sides," Bush said at a press briefing.

Formal negotiations on a free-trade agreement are scheduled to begin Tuesday in Washington. Because of the importance of the talks to Canada, Mulroney will address a nationwide television audience on the subject Monday night.

The negotiations are seen as a make-or-break issue for the Conservative government, and their outcome could determine Mulroney's fate in the next election.

Completing a two-day formal visit, Bush said the recent U.S. action imposing a 35 percent tariff on Canadian cedar shakes and shingles, which prompted an angry wire from Mulroney to Reagan, was taken "under an established and open process to enforce the existing trade laws of the U.S."

"The facts showed that our shakes-and-shingles industry had been seriously injured, and we acted," Bush said. The industry provides cedar siding and roofing for homes.

Calling the shakes-and-shingles issue a "tiff" because it made up a minuscule portion of the $120 billion two-way trade, Bush urged Canadians to forget the matter "and focus on the road ahead."

Earlier in the trip, he told a Vancouver audience the United States wants expanded trade and a healthy, growing relationship. "We do not want a trade war," he declared.

He said the recent launching of a countervailing-subsidy investigation against Canadian softwood lumber -- a major export worth several billion dollars a year -- was also done in accordance with U.S. trade laws, and is still only in its earliest stages.

Bush said he told the prime minister that U.S. protectionist sentiments were very strong and pointed out that Canada accounted for $20 billion of America's $148 billion trade deficit. He said no nation, including the United States, was pure when it came to protectionism or the use of subsidies. But he reaffirmed the adminstration's and his own personal commitment to free trade, and promised to promote it "as long as I am in public life."

The vice president acknowledged that, during discussions with Mulroney about recent U.S. trade sanctions, the prime minister "pulled no punches."

The United States, however, had trade complaints of its own. Under Canadian law, for example, Canadian pharmaceutical firms can't be denied access to patents held by foreign firms, Bush said.

"I'm going back with a strengthened view of Canada's concerns," he said.