Warnings by opposition presidential candidate Corazon Aquino that she would put Philippine President Ferdinand Marcos on trial if she wins an election set for February are causing alarm both in the Marcos camp and among her own supporters.

Aquino first made the statement last week as she was trying to unify an opposition ticket, and she has repeated it since then to the growing consternation of Marcos.

Aquino has said repeatedly that she seeks justice, not vengeance, in the case of her late husband, Benigno Aquino Jr., who was assassinated at the Manila International Airport in August 1983 in the custody of military guards.

While sympathizing with Aquino's feelings, opposition figures expressed concern today that her remarks about putting Marcos on trial were injecting a potentially dangerous element into the campaign and might prompt Marcos to scuttle the election.

In an interview last week with a regional news magazine, Asiaweek, Aquino said that if she wins the election, Marcos "will be given justice. I guess that means a trial."

Marcos reacted sharply when he opened his campaign last week in Batangas Province. Speaking at the Fernando Air Force base, he suggested that military men and government officials also could face action against them and urged them to rally behind his candidacy.

In other statements, Marcos also has repeatedly raised the prospect that a move to put him on trial for the murder of Benigno Aquino could trigger fighting between his supporters and Aquino's.

In a speech before a youth group at his Malacanang presidential palace yesterday, Marcos asked what would happen to Filipinos in the event of an opposition victory.

"Are we going to have another Vietnam, another Kampuchea, another Iran, Nicaragua, El Salvador?" he asked. "Are we going to end up with a civil war? I say no, we are not going to."

Marcos also questioned whether the entire platform of Aquino was to send him to jail. He then implied he would resist, wondering aloud whether troops could be sent to arrest him if he returned to his home region in the northern Philippines.

Marcos reacted again today during a campaign visit to his home province of Ilocos Norte when he raised Aquino's latest statement in a New York Times interview Sunday that she would file charges against Marcos if she won the presidency.

Addressing a crowd in the provincial capital of Laoag, Marcos accused Aquino of seeking the presidency only for personal vengeance and of having no program of government.

In a statement today to counter accusations of vindictiveness, Aquino said through a spokeswoman: "I must emphasize again that in seeking justice, there must be no vengeance or ill feelings towards anyone. The law must be applied equally to all, then let mercy and compassion, as dictated by God-like tenets, take care of the rest."

A court this month acquitted 25 military men and one civilian charged with involvement in her husband's murder and a subsequent coverup. The verdict has been widely condemned here and abroad as a travesty of justice. Critics have charged that the Philippine judicial system is no longer independent.

"Many of us in the opposition feel Cory [Aquino's nickname] should not put it that way," said one legislator, referring to her remarks. "People are advising Cory not to be hasty and make unnecessary remarks like that."

Aquino's statements are "very ill-advised," said Raul Gonzalez, a lawyer who sides with the opposition. "They are statements that will harden Marcos."

Gonzalez made the comments at the Supreme Court following a hearing on the constitutionality of the Feb. 7 election. Marcos, 68, who has been in power for 20 years, called the early election more than a year before his term is scheduled to end in a bid for a "new mandate from the people." Opposition petitioners have challenged the early poll on grounds that, according to the constitution, Marcos must resign before such an election can be held. Instead, Marcos has submitted a post-dated letter of resignation effective after the voting.

The Supreme Court today scheduled another hearing for Wednesday after hearing arguments for and against a law that set the early election. A ruling that the law is unconstitutional requires the votes of 10 of the court's 13 justices, all of whom have been appointed by Marcos. If fewer than 10 justices voted to strike down the law, the law would be upheld.

Lawyers and opposition politicians said today they believed the majority of the justices opposed the law, but that it remained to be seen whether as many as 10 would vote against it. Despite the protestations of Marcos that the Supreme Court is an "independent body," these sources believe the outcome of the issue will reflect Marcos' wishes.

"The probability is very strong that the election might just be called off," said opposition legislator Luis Villafuerte. He noted that Marcos' ruling New Society Movement had not bought radio time for advertisements, distributed posters and campaign literature to any significant extent or disbursed money to begin the campaign in the provinces.