More than 650 people, including four National Assembly candidates, were arrested here yesterday for protesting martial law under Philippine President Ferdinand Marcos. Four other opposition candidates went into hiding.

It was the first time in several months that the Marcos government had resorted to mass arrests to block peaceful protest and indicated a sudden return to harsh action against dissidents after a relatively free election in the former U.S. colony. Yesterday's arrests came when police stopped a protest march that was significantly smaller and quieter than many opposition marches allowed before Friday's election.

"They gave us a short taste of freedom, but now Marcos' people will see that martial law is grossly enforced," said former Senator Lorenzo Tanada, manager of the anti-Marcos election slate in Manila, as he was booked for illegal assembly.

Later, a government controlled television station said all those arrested would be charged with sedition.

A return to the pattern of harsh repression and underground rebellion of the early days of martial law could severely jeopardize Marcos' chances of winning U.S. approval for a new and more lucrative military bases agreement.

After halting yesterday's march, police commandeered six public buses on busy Espana Street, told the passengers to get off and loaded on the marchers, who were protesting alleged vote fraud which they say swung the election to the pro-Marcos slate in Manila. All except eight leaders of the afternoon march was taken to Ft. Bonifacio, the huge army base where opposition leader Benigno Aquino is serving his sixth year in prison for martial law offenses.

Ft. Bonifacio officers, ordering a reporter who followed the buses off the base, refused to give any information about the arrests. The eight protest leaders were later found being booked at police headquarters several miles away. Each was given a physical examination, police said, to guard against charges of police brutality. Both the arrested leaders and the arresting officers said they did not know when those arrested would be released.

Marcos told a nationally televised press conferance Saturday that "undoubtedly the subversives have infiltrated Laban," the acronym meaning "fight" used by the anti-Marcos campaign slate in Manila. He warned he would take preventive action to stem potentially violent protests and said police were looking for one opposition candidate, attorney Charito Planas, on suspicion of harboring communist guerrillas.

Opposition sources said yesterday that Planas and three other candidates tied to the student-worker-slumdweller movement - Trining Herrera, Jerry Barican and Alexander Boncayao - had gone into hiding to avoid possible arrest.

Some Marcos supporters have complained that U.S. pressure on the human rights issue forced Marcos to call Friday's election for an interim National Assembly, the country's first election in more than six years, sooner than he wanted to. Both Marcos and his wife Imelda, the leader of the pro-Marcos slate in Manila, made heated charges of American interference in the last days of the campaign. Marcost said he "could no longer stomach" what he said were U.S. attempts to persuade him to free Aquino.

Counting of the estimated 23 million votes cast nationwide Friday proceeded slowly. The commission on elections released official totals for about 5 per cent of all precincts in Manila, which showed the pro-Marcos slate sweeping all 21 Assembly seats for the city and holding a 2-1 edge over the opposition led up Aquino.

Aquino was quoted by a relative yesterday as saying, "The moral victory will last longer than the victory of numbers." Opposition poll watchers have charged that government officials stuffed boxes with pro-Marcos ballots before polls opened and stole or mutilated opposition ballots at the end of election day, most opposition poll watchers visited at random Friday said they had no major complaints, however.

After Marcos post-election warning of preventive action against protest, opposition leaders waited a day and then, despite dissent from some more cautious members called yesterday's march headed by two coffins symbolizing what they said was the death of whom were young, to avoid any trouble along the way from St. Teresa College to an afternoon mass at the Manila cathedral. They said they which Marcos said had occurred at a boistrous election-eve "noise barage" that caused automobile damage and one reported death.

When a squad of about 35 police ran out in front of the marchers a little less than half way to the cathedral, eight of the leaders linked arms and then climbed into a police van when ordered to do so. Tanada, the campaign manager, who will be 80 in a few weeks yelled "Laban" and shook his fist at the younger marchers, who returned the salute.

Each time the marchers ignored a loud speaker order to disperse, police Maj. J.D. de Jesus spoke into his walkie-talkie, asking instructions. Finally the buses were commandeered and the marchers filed in without incident.

"They wanted to recreate an atmosphere of fear in the country," former Senator Francisco Rodrigo, one of the candidates arrested, said while being booked. Arrested with him were his son, King, an attorney; candidates Nene Pimentel, Ernesto Rondon and Teofisto Guingona; Guingona's wife, Ruthie, and an attorney representing Laban, Joker Arroyo.

The four arrested candidates, like seven other of the 21 Laban slate members, had been jailed for several weeks in the early months of martial law.

Rodrigo said that despite the loss of the election, the opposition had been able to publicize its case against martial law and win many more supporters. "We had seminars for people to talk about martial law before this election," he said. "Now I think we'll be talking to and organizing much larger groups."

Throughout the march and while boarding the buses, the marchers softly sang an old song, "My Philippines, Our Only Dream Is to See It Free." It dates back to the era when the islands were under Spanish, and then American, rule.