The Reagan administration again increased its steadily growing pressure against Panamanian strongman Gen. Manuel Antonio Noriega yesterday by backing the civilian president who sought to fire him and initiating a U.S. diplomatic campaign to support "civilian constitutional rule" in Panama.

The administration said it continues to recognize Eric Arturo Delvalle as president of Panama, even after Noriega and the National Assembly ousted him yesterday for seeking to dismiss Noriega as the country's military chief.

Late in the day the White House announced the initiation of "a series of consultations to learn the views of other countries in the hemisphere" on the Panamanian developments.

State Department officials said U.S. ambassadors throughout Latin America have been instructed to pose the issue to their host governments as a choice: "military dictatorship versus civilian rule."

President Reagan, in comments to reporters at a photo-taking session, rejected U.S. military action to oust Noriega and said he did not believe that the 9,800 U.S. military personnel and their 13,000 dependents stationed in Panama are in danger.

"I do not think there is any appetite on their {Panama's} part, including Noriega," for any attacks on U.S. forces, Reagan said.

"We think there are limits on what we can do. We're looking at that situation . . . to see if there is anything we can do. We're not prepared to take military action," said Reagan on a day when he met with his senior National Security Council advisers on the Panama developments.

U.S. policymakers were aware in advance that Delvalle would attempt to use his civilian authority to oust the entrenched military leader, and said they were not surprised that Noriega ignored the ouster order and deposed the civilian president.

The action, although ineffective in the short run, was viewed as a potentially important step in the confrontation with Noriega because of its possible impact on political leaders of other Latin nations and its potential effect in Panama. Noriega was indicted by federal grand juries in Miami and Tampa early this month on drug and racketeering charges.

Additional U.S. steps are likely within the next few days, including a presidential order imposing economic sanctions against Panama Tuesday under a recent law designed to combat foreign drug traffickers.

This action would require U.S. votes against loans or grants to Panama in the Inter-American Development Bank, the World Bank and other multilateral financial bodies.

The United States halted military and economic assistance to Panama last July in an earlier stage of the struggle with Noriega.

A more serious action being discussed in the administration and on Capitol Hill is an embargo on U.S. trade with Panama. Sen. Alfonse M. D'Amato (R-N.Y.), accusing the administration of sending "mixed signals" to Noriega, urged imposition of a trade embargo and said U.S. military action should not be ruled out.

Vice President Bush, campaigning in Greenville, S.C., said the United States should reserve to the right to do "whatever is necessary, including military force," to protect what he described as "sacred" U.S. interests in Panama.

Senate Democratic leaders, however, took a more cautious, keep-the-powder dry approach. The chairman of the Senate Select Committee on Intelligence, David L. Boren (D-Okla.), said after a briefing by top CIA officials, "I think caution has to be the watchword right now."

Boren noted that the United States is spending $500 million yearly on U.S. troops and dependents in the Canal Zone, which could presumably be reduced, but he cautioned against "hasty action until we can look at our national interests" and consult with leaders of democratic countries in the hemisphere.

U.S. military personnel in Panama have been instructed to limit "personal movements" and spend as little time as possible in public places, according to Pentagon officials.

"If they do not live on bases, we're asking them to stay around their residences," a military spokeswoman said. "We want them to have decreased visibility."

Assistant Secretary of State Elliott Abrams met early yesterday with Juan B. Sosa, Panamanian ambassador to Washington, who announced that Noriega had instructed him to resign for supporting Delvalle.

Sosa said he is refusing to step aside and still considers himself the lawful emissary of his country.

"Gen. Noriega said he understood my position {but} I'm sure he will try to find another ambassador," Sosa said at a news conference.

An informal meeting of the Organization of American States (OAS) here broke up in confusion when two competing ambassadors from the two contending factions in Panama claimed to represent that country.

"Now we have two of everything: two presidents, two OAS ambassadors and two foreign ministers," said Lawrence Chewning Fabrega, the competing envoy who supports Delvalle.

Staff writers Helen Dewar and Molly Moore contributed to this report.