Republicans at the Tidewater Conference, concerned that any expression of disagreement with President Reagan might be construed as an election-year breaking away from him, today passed resolutions broadly supporting his Latin American and economic policies.

The only possible note of criticism at the fifth annual conference came in the economic resolution, which urged that the federal budget be balanced by 1985 and supported a constitutional requirement if necessary to achieve a balanced budget. The administration has stopped predicting a date for balancing the budget.

The conference is made up of members of Congress, statewide office holders and the top two officials of the Republican Party, who meet annually to draft policy positions for Republicans.

The group passed a resolution backing the administration's dealings with Mexico on a solution in El Salvador. It also endorsed Reagan's "New Federalism" plan that would transfer some federal programs and tax revenues to the states.

It tabled a fourth resolution that would have endorsed congressional curtailment of the jurisdiction of the Supreme Court and lesser federal courts over "constitutional issues" such as abortion, school busing and school prayer.

The leaders of the conference had invited Reagan. He declined with thanks, but the conferees debated and voted the nonbinding resolutions figuratively looking over their shoulders at the White House, as though they were wondering whether the president was watching and listening.

"Everyone was afraid that with the headlines in the past few weeks that whatever we say here that might sound as though we were disagreeing with the president would be taken as a sign that we're all bailing out on him," said Rep. James G. Martin (N.C.).

He was referring to a recent interview in which Sen. Bob Packwood of Oregon, one of the Tidewater Conference founders and leaders, criticized Reagan's perception of crucial issues such as the budget deficit, and contended that Reagan was weakening the party with minority groups. Recent newspaper stories have reported that Republican congressmen were putting distance between themselves and the president in this election year.

Martin and others expressed relief after the first day's session ended that the potentially controversial resolution on Latin America had been so amicable.

Nevertheless, the conferees appeared to be notably less gung ho for the president than last year, when he was riding the crest politically.

The El Salvador resolution as presented to the conference was terse and hawkish: "Resolved that the United States maintain all options, including the use of armed force, in order to protect our interests in Latin America."

The resolution finally approved by the conference called on Congress to implement Reagan's proposed increased trade, economic and technological assistance and economic development by the private sector in Latin America, for Congress to encourage free elections in the area, including Nicaragua and Cuba, and for Congress and the administration to continue to contain "Cuban aggression" and interference by foreign powers in their internal affairs.

It concluded by saying that the "government of the U.S. should seriously consider the offer of the government of Mexico or other appropriate offers to serve as a third-party intermediary to bring if possible a solution to Central American problems."

This amendment was advocated by Rep. Joel Pritchard of Washington, who argued that Latin Americans are more likely to listen to Mexico than the United States.

Sen. Alan K. Simpson of Wyoming and Rep. Robert J. Lagomarsino of California argued that failure to stabilize Latin America could result in millions more immigrants fleeing both into Mexico and into the United States.

"If we don't face up to the problem and if some countries come under dictatorial regimes such as Guatemala, the immigration problem will be overwhelming," Lagomarsino said.

Simpson added that there can be no solution in the Caribbean region without Mexican participation. "The Mexican population will double in the next 20 years," said Simpson, who is chairman of the Senate subcommittee on immigration. "We are going to have to create 600 million jobs in that area, in that period, more than there are now in all the industrialized nations."

The debate on balancing the budget called on Congress "during its consideration of the budget to take all the steps necessary, including a constitutional amendment, to restrain spending growth and stimulate economic growth through a consistent, incentive oriented tax policy with the goal of increased employment and a balanced budget."

During the debate, several conferees argued that no segment of the budget, including the Defense Department, would be "sacrosanct" in considering spending cuts.

The conference concludes Sunday with a morning session in which miscellaneous resolutions and debating points from today's resolutions will be brought up.