Former secretary of state Henry A. Kissinger planned to arrive in Washington Monday to begin his examination of U.S. policy in Central America, as Democratic leaders in Congress yesterday questioned the value of the commission he will head and demanded more information about planned military maneuvers in the region.

Administration officials said Kissinger is to meet with President Reagan and national security affairs adviser William P. Clark. He also is to hold a news conference to discuss the scope of work to be tackled by the bipartisan commission Reagan appointed early this week.

The commission is intended to help the nation reach a consensus about the proper policy for Central America, where a U.S.-supported government in El Salvador is facing leftist insurgents and U.S.-supported insurgents in Nicaragua are challenging a leftist government.

But Senate Minority Leader Robert C. Byrd (D-W.Va.) yesterday said he fears that the commission is only a "smoke screen for the administration to get its way" on Central American policy. The U.S. Conference of Catholic Bishops also criticized administration policy in the region.

House Democrats, meanwhile, were preparing for a showdown next week on U.S. covert funding of anti-Sandinista insurgents in Nicaragua. And two House leaders demanded information about military maneuvers set to begin next month.

"We are very concerned about the level of tension in the area, particularly along the border between Honduras and Nicaragua," the chairmen of the House Foreign Affairs Committee and its Western Hemisphere subcommittee wrote Defense Secretary Caspar W. Weinberger. "Conducting military exercises in Honduras involving U.S. forces could have serious implications for U.S. commitments in the region."

As a result, Reps. Clement J. Zablocki (D-Wis.) and Michael D. Barnes (D-Md.) requested "consultations" as soon as possible.

Fred C. Ikle, undersecretary of defense for policy, said this was being worked on.

Ikle yesterday canceled a briefing about the planned maneuvers, which administration officials have said will involve as many as 5,000 men and a series of carriers and battleships in the next six months. Administration officials said the increased U.S. military presence is intended to intimidate the Nicaraguan government and show support for friendly nations.

Ikle's briefing was meant partly to tone down rhetoric about the maneuvers, according to one official. It would have pointed out, for example, that the United States has no plans to establish a naval blockade between Cuba and Nicaragua, although Reagan did not rule that out during a news conference Thursday.

Pentagon officials said the briefing was canceled partly out of deference to Congress and partly because of nervousness on the part of the Joint Chiefs, who want to wait until Honduras has agreed to all the details before announcing the plans.

The administration's rhetoric about Nicaragua prompted a strongly worded speech from Byrd questioning the bipartisan nature of Kissinger's panel.

"In the same week the national commission on Central America is announced," Byrd said, "we learn that the administration is planning massive and extended military maneuvers in the area and that the administration is going to ask for $400 million in additional economic and military aid for Central America.

"It almost sounds as if the commission, which I doubt has had an opportunity to even sit at the same table, has already had its decisions made for it."

The Catholic bishops issued a statement calling for diplomatic efforts to reduce tensions and criticizing the administration's "unrelentingly hostile policy rhetoric."

"U.S. policy toward Nicaragua presently has the effect of deepening the internal crises in the country and escalating the dangers of war in the region," Archbishop John R. Roach of St. Paul-Minneapolis said on behalf of the conference.

That policy may be tested next week when the House considers a proposal to end covert funding for the anti-Sandinista guerrillas. The amendment, which the administration strongly opposes, was debated in an unusual secret House session Tuesday.

The amendment would replace covert aid with an overt aid program aimed at interdicting arms moving from Nicaragua to leftists in El Salvador. None of the funds could be used in Nicaragua or directly against the Sandinista regime.

House Whip Thomas S. Foley (D-Wash.) told reporters yesterday that he believes that the vote will be close. Other Democrats said head counts show the vote to be "very close," but with many members still uncommitted.