Amid angry charges of vote fraud from the opposition, candidates backed by Philippine President Ferdinand Marcos appeared headed for victory in the first election since his 1972 declaration of martial law.

Early returns this morning in the balloting for an interim national assembly showed the pro-Marcos New Society Movement slate holding a 3-to-2 edge over an opposition group of candidates in the greater Manila area. The capital city is the only region where an outspoken and well-organized anti-Marcos group contested yesterday's election.

In some Manila neighborhoods where opposition leaders charged massive ballot box stuffing, the pro-Marcos slate enjoyed margins of as much as 100-to-1.

Although Marcos appeared close to a clean sweep over his opponents, the fraud charges and threatened protest demonstrations could hurt one of his key interests in holding the election. He had wanted to smooth the way for an expected lucrative new military bases treaty through a U.S. Congress upset by martial law abuses here.

While the new interim asseimbly is unlikely to pose any challenge to Marcos' martial law powers, the president had run the risk of exposing himself and his wife Imelda, who is governor of greater Manila, to compaign attacks from opponents and some free choice on the part of voters in a way that would attract the attention of the world press.

After an electrifying television performance halfway through the campaign by the leader of the opposition slate, former senator Benigno Aquino Jr., the Marcoses began to use their patronage powers to win more votes. New benefits for teachers and other government workers, crucial to any victory in Manila, were soon announced.

On the basis of returns so far it could not be determined if Aquino will win an assembly seat.

Imelda Marcos, who headed the pro-martial law ticket in Manila, had only a slim lead over other New Society Movement candidates in this morning's early returns. A failure to outpoll other members of her slate, such as 79-year-old Foreign Secretary Carlos Romula would be embarrasing, considering the great amount of time she spent campaigning and tremendous personal publicity that included putting only her picture on the slate's principal posters and handbills.

As charges between the pro-and anti-Marcos groups increased in vehemence yesterday, police raided the home of one opposition candidate in Manila and reportedly detained, at least temporarily, dozens of anti-Marcos poll-watchers.

Following the discovery of a time bomb outisde the national police headquarters and an oppostion-inspired "noise barrage" in Manila Thursday, Marcos said yesterday, "I warn subversives who are apparently on the warpath not to keep taxing the patience of our people."

Despite the reported election abuses, yesterday's voting around most of Manila appeared orderly and peaceful, in a country where shootings were often common around election day before martial law.

A random check of eight major polling places found only one where opposition poll-watchers complained of significant abuses. There were some precincts with no opposition watchers, either because of shortages of volunteers or because local officials barred them from the polls. In such areas the abuse charges were most frequent.

In the Manila suburb of Las Pinas, where the opposition slate held a well-attended rally at the end of its campaign, the pro-Marcos mayor and some aides allegedly brought hundreds of ballots already marked for the Marcos slate into polling places. Early returns from Las Pinas last night showed the pro-government slate winning some precincts by 200 to 0 and 244 to 0 margins.

Spokesmen for the opposition People's Power slate, said last night that they still hoped to win some of the 21 assembly seats being contested in Manila. Early returns showed some of their candidates winning in scattered precincts.

In a flurry of rumors and confusion as foreign journalists dashed about the city checking reports of election abuses, at least one foreign reporter was detained briefly and another was roughed up by police.

An anti-Marcos group called the Citizens Movement for Freedom called for an all-day noise barrage today to follow Thursday night's one-hour blast of horns, trash cans and voices. "Let's show our fellow citizens who are still afraid that the majority is awake and not asleep, upright and refusing to kneel," the group said in handouts.

Opposition spokesmen expressed concern about a police raid yesterday on the home of Charito Planas, a lawyer and former martial law detainee who has been a harsh government critic. Opposition members who witnessed the raid said Planas was not there at the time. Early this morning they said they did not know her whereabouts.

Interviews with voters leaving the polls showed a majority supported continuation of martial law, if only to allow Marcos to continue his road- and building-construction programs unhindered by congressional review. Yet many people said they hoped some opposition candidates would serve as a small check on his power.

"Martial law is good for business," said Bing Chua, a Makati businessman, "but I don't like a lot of this corruption."

"If he says the teachers get a pay increase, we get it right away," said Belen Herreros, 49, who teaches at a school for the deaf. "In the old days the Congress could hold it up a long time. Still, my son's voting for Aquinio and that's all right."