President Ferdinand Marcos rejected today an opposition charge that he might declare martial law to avert defeat in a presidential election set for Feb. 7. He predicted an easy victory and said he would consider martial law only if Communist rebels attacked Philippine cities.

"I don't think there are any reasons to doubt the elections will be held," Marcos said at a news conference. "They will not be aborted. And we intend to win the elections."

Marcos said a major problem for his party now is "that we might win by such a big majority that it would be incredible." He added, "We are trying to win by a credible majority." He said he hoped he would get "a little bit" less than the 92 percent of the vote that he said he won in a 1981 election. He said 60 percent was a landslide by U.S. standards and that "we might get more than that."

Marcos also said he stood by his invitation to foreign observers to monitor the elections, in which he and vice presidential candidate Arturo Tolentino, 75, are running against Corazon Aquino and Salvador Laurel.

The Marcos-appointed Commission on Elections, known as Comelec, issued guidelines today barring foreign observers from entering polling places, but it said they could observe the counting of votes later at Comelec.

The ruling was issued as a bipartisan delegation of U.S. political and election experts worked to draw up a plan for observers to monitor the elections.

A leading member of Marcos' ruling New Society Movement, Arturo Pacificador, charged yesterday that the delegation's request to Comelec for access to polling places was "intervention of the highest order." He said that if foreign poll-watchers "want to observe, they should remain as observers and not as intruders."

In his news conference today, Marcos said he hoped that the observers' "presence will add credibility to the entire exercise" of holding elections more than a year before Marcos' current six-year term is due to expire. Marcos called the election in November to seek a "new mandate" in the face of American pressure for wide-ranging political, economic and military reforms.

Suspicions have persisted among opposition politicians that Marcos could call off the poll if he perceives that he might lose. Aquino said Wednesday during a campaign stop that she thought such a scenario was possible.

Marcos declared martial law in 1972 a year before his second four-year term was to expire. He scrapped a U.S.-style constitution that limited him to two terms and ruled for nearly nine years under martial law before lifting it in 1981. He was reelected to a six-year term in June 1981 in an election boycotted by major opposition groups.

"Unless there is any fighting in the streets of the cities, there is no reason to proclaim martial law," Marcos said. He said the Communist Party of the Philippines and its armed wing, the New People's Army, which are waging a guerrilla war in the countryside, are incapable of attacking cities.

Addressing local and foreign reporters in the Manila Hotel, Marcos warned that an opposition victory could lead to a bloodbath because of fighting between the military and Communists. He raised the possibility that the armed forces might take over in the event of an opposition victory. If a "weak" president assumes office and Communists acquire power in the government, "of course there will always be a reaction, not only from the military but from the people," Marcos said. "Then you might have a civil war."