Philippine President Ferdinand Marcos' order yesterday for the arrest of 30 opponents, including some exiles living in the United States, is putting the Carter administration and Philippine opposition groups here in a tight spot that could lead to an unwanted confrontation.

Marcos has accused several leading exiles of involvement in a wave of terrorist bombings, the latest of which injured as many as 20 persons, including seven Americans, in Manila Sunday.

The leading Philippine opponents of Marcos here yesterday denied any connection with the mysterious April 6. Movement, which has claimed responsibility for many of the bombings, including Sunday's blast at the annual convention of the American Society of Travel Agents. However, the U.S.-based opponents interviewed said that while they disapproved of the group's terrorist tactics, they sympathized with its stated aim of restoring democracy to the Philippines after eight years of Marcos' authoritarian martial-law rule.

The Carter administration has advised all the Philippine opposition groups and leaders here that they can say what they want, but may face prosecution if they are connected with antigovernment violence in the Philippines, according to State Department officials.The United States could not send any exiles back to the Philippines, however, since the two countries do not have an extradition treaty.

While the administration apparently has stopped short of a crackdown on the groups or a full-scale investigation as demanded by Marcos, it apparently is keeping a close eye on the exiles' activities in an effort to mollify the Philippine strongman. The Philippines has long been a close ally of the United States, with the two governments bound by a defense treaty.

"We're standing on one foot on a chalk line right now," a State Department was awaiting promised evidence from the Philippine government that would link some of the exiles here with the terrorist bombings in Manila. If the Philippines provides the evidence and the Justice Department deems it substantive, an investigation could be ordered into possible violations of U.S. laws, the official said.

"We will not investigate any political organization unless we have evidence they are breaking the law," the official said.

Any established link with the Manila bombings could be punishable under the U.S. Neutrality Act, which prohibits conspiracies to forcibly overthrow allied governments, or of the Arms Export and Munitions Control Act, which bars the unauthorized export of arms and explosives from the United States, officials said.

So far, officials said, there is no evidence to support Philippine government allegations that anti-Marcos terrorists have set up training camps in Arizona and California and that moderate Philippine exile leaders here have masterminded the bombings.

But contacts between these leaders and members of Philippine guerrilla groups, as well as a tendency toward radicalization of the opposition in general, have contributed to suspicions that a "U.S. connection" may exist. In addition, according to Philippine sources, this radicalization may be threatening an otherwise cordial relationship between the moderate opponents of Marcos and the State Department.

Among the opponents Marcos has blamed for the bombings, and whose arrest he now is seeking, are former senator Benigno Aquino Jr., who currently is a fellow at Harvard University's Center for International Affairs.

Aquino came to the United States in May for a heart operation after serving eight years in jail in the Philippines for his opposition to Marocs. In a telephone interview yesterday, Aquino called Sunday's bombing "unfortunate," but said that Marcos had only himself to blame for it.

"I am against violence, but you cannot close that option totally," he said. I sympathize with these people trying to regain their freedom, but I disagree with their tactics."

While denying involvement with any Philippine guerrilla group, Aquino said, "I support any opposition to Mr. Marcos." He said that the April 6 Movement had sought his leadership in two unsolicited manifestoes sent to him -- the latest dated Sept. 27, 1980 -- but that he did not know the group's members and "would like to know what their overall plan is."

Aquino said, however, that while recovering in Dallas from his heart operation he had been visited by three men who "outlined plans for bombings" in the Philippines and by members of the Moro National Liberation Front, a Moslem guerrilla group fighting for autonomy in the southern Philippines. He said that in July he went on a trip during which he learned about guerrilla "training grounds in Latin America and the Middle East," Aquino said he visited Damascus, Syria, and met leaders of the Moro group, which has been financed and trained by Libya. However, Aquino would not specify which Latin American countries he visited or where the purported training camps were.

Another opponent whose arrest is sought by Marcos is Raul Manglapus, the leader of the Movement for a Free Philippines.

He ridiculed the charge that he was linked to the recent bombings, saying, "It's very convenient to order the arrest of people who are not there." He added, "They give us too much credit to be able to start things from 10,000 miles away."

Manglapus said his group "does not counsel indiscriminate violence" such as Sunday's bombing, but that "we cannot condemn the motives announced by the April 6 Movement."