Leaders of the world's seven richest nations, having resolved or at least papered over disagreements on Third World debt and farm subsidies, turned their attention Monday to a discussion of President Reagan's arms control initiatives and other foreign policy concerns.

The officials began their second day of talks aimed at drafting a final political communique. The United States was pushing for inclusion of a proposal to prohibit airplane hijackers from refueling.Senior officials from the seven summit nations had worked into the early morning hours Monday on the wording of proposals endorsing the U.S. arms control negotiations with the Soviet Union and a call for further negotiations to reduce non-nuclear forces in Europe.

Reagan, arriving for the talks, held in a windowless basement room of the Metropolitan Toronto Convention Center, was asked about a coup in Haiti which overthrew civilian president Leslie Manigat.

"We are assessing that right now," said Reagan. The president did not respond at all when asked for his opinion of a breakthrough agreement announced Monday with Japan that resolved a lengthy dispute over U.S. access to the beef and citrus market.

The landmark agreement calls for Japan to lower tariffs on beef and oranges over the next six years with U.S. officials predicting it could double the value of U.S. beef exports to the country, pushing them to more than $1 billion annually.

The 14th annual economic summit meeting between leaders of the United States, Japan, West Germany, Britain, France, Italy and Canada began on Sunday and is scheduled to conclude with a final economic communique on Tuesday.

At the opening session, the Western leaders quickly decided to play down a contentious dispute involving farm subsidies and approved in principle a debt-relief package for the poorest countries of the world.

The leaders pledged in a statement after their first session Sunday afternoon to continue their close economic cooperation, which they credited for keeping the world economy out of a recession following the October stock market collapse.

"We all feel we have made real progress in recent years. Our message is and should be one of confidence and optimism in dealing with the challenges confronting us," the leaders said.

In an effort to moderate their generally optimistic tone, the leaders interjected a note of caution in their joint statement, which was issued by Canadian Prime Minister Brian Mulroney.

"There is no room for complacency. Difficult challenges remain," the statement said. "Our countries must develop further our economic coordination efforts. Sound policies must be continued."

U.S. Treasury Secretary James A. Baker III echoed the positive statement Monday, saying, "I think there is to some extent an air of satisfaction, but I must say I don't believe it's an air of complacency."

Baker, interviewed by CBS-TV, said finance ministers had engaged in an extensive discussion on inflation and that "the general consensus (s) that while we must remain vigilant, we think it is pretty well under control."

The U.S. official described the ministers as "pleased with the degree of exchange rate stability" that exists and have found "the world economy is in pretty good shape."

On the agenda were two formal sessions and a dinner designed as a brainstorming session on long-range problems. Closing ceremonies are scheduled for Tuesday.

A 3,000-member security force has turned Canada's largest city into something of an armed camp. Guards were stationed on rooftops, patrolled Lake Ontario in speedboats and hovered overhead in helicopters.

Some 1,500 demonstrators, protesting a variety of causes, defied a police ban and attempted to march to the summit site on Sunday. More than 130 protesters were arrested when they hurled themselves over police barricades into the arms of riot control officers.

Reagan pronounced himself happy thus far with his eighth and final economic summit, a gathering the administration is hoping will spotlight Reagan's free-market economic policies.

"We are on the right track and we have to stay on it," Reagan was quoted by an aide as telling the government leaders during their first meeting.

Asked later why the initial session lasted 45 minutes longer than had been planned, Reagan told reporters, "We had a lot to talk about."

Previous summits have featured at times pointed criticism about America's huge budget deficits and failures of such countries as Japan and West Germany with huge trade surpluses to do enough to promote domestic demand.

But such talk has been banished from this gathering, in part because the world economy is doing well this year, with economic growth accelerating in most major countries and unemployment levels falling to the lowest levels of the decade.