Philippine President Ferdinand Marcos, in a shift, said today that he will let parliament make the final decision on whether to hold an early presidential election and said the vice presidency will also be contested in such an election.

In a series of surprise announcements in recent days, Marcos said he was ready to call a "snap" presidential election on Jan. 17, well ahead of the planned 1987 contest, and that he intended to issue a decree allowing him to run without resigning. He also said Monday that the vice presidency would not be contested because "the issue is Marcos."

But a statement today by the presidential palace said Marcos had decided against issuing a presidential decree "that will govern the election." Instead, he said, "We will throw everything to the Batasang Pambansa [National Assembly], and it is up to the Batasang to decide whether to hold the special elections or not." Marcos's ruling party controls a two-thirds majority in the assembly.

Marcos also said the vice presidency, which has been vacant for 13 years, would be included. "It is now apparent that the complexion [of opposition criticism] has changed from Marcos to that of his entire administration and his entire program of government," the statement said. The statement said stability of the government through the succession mechanism could be established only if there were a vice president.

The change by Marcos came in the face of strong criticism from the opposition and members of Marcos' ruling party that a snap presidential election would be illegal unless Marcos first resigns from office and that the continued vacancy of the vice presidency would add to political instability.

Under the constitution, a special presidential election can be held only if the office becomes vacant. Marcos' current six-year term ends in 1987.

After he announced the election in a U.S. television interview Sunday, government officials said Marcos was considering a special decree with a provision to allow him to run without stepping down.

The latest presidential palace statement left open the question of whether Marcos intends to resign. But U.S. officials who have been following the situation closely said that it is likely that Marcos will want to remain in office. Instead of putting the mechanisms for such an election in place by decree, these analysts said, Marcos' strategy of turning the whole question to parliament would enable the opposition to participate and therefore counter opposition criticism about how the election is set up.

Marcos said two caucuses of his ruling New Society Party will be held Friday and Sunday to decide how to present the special election package to parliament.

In Washington, the State Department said: "Obviously the timing of the election impacts on the issues of fairness and credibility." On the vice presidency, the department warned that "if the next presidential election in the Philippines does not address the succession question, political stability will be affected adversely."

On the vice presidency, Marcos did not say who his running mate will be. It has been speculated widely in the past that Marcos was grooming his politically powerful wife, Imelda, as his eventual successor.

Cecilia Munoz-Palma, chairman of the National Unification Committee that is responsible for choosing a single opposition candidate, said the committee will meet after Marcos held his party caucus.

"We doubt the sincerity of Marcos," she said. "We can't really say for certain that an election will be held as stated. . . . He has a record of broken promises."

Earlier this summer, Marcos threatened to call early elections to stave off an opposition move in parliament calling for his impeachment, but later reversed himself.

Corazon Aquino, 52, has emerged as the most likely candidate behind whom the opposition could unite. Today's announcement on the vice presidency has focused attention on the other two main opposition candidates, Salvador Laurel, 56, head of the United Nationalist Democratic Organization known as Unido and Jovito Salonga, 65, leader of one wing of the Liberal Party.

In Washington, Laurel warned that the Philippines would "explode" either in a Communist takeover or a preemptive military coup if the forthcoming elections were not honest, Washington Post staff writer David B. Ottaway reported.

[Laurel, already the presidential choice of his group, said he would back Aquino as the presidential candidate if the other three major parties agreed.]