President Corazon Aquino, stepping up efforts for reconciliation with the country's armed communist insurgents, indicated today that she does not expect rebel leaders to respond sincerely to her call for a negotiated peace, but said she is "willing to take the gamble to avoid any further waste of life."

Her statement followed two major highway ambushes Friday and yesterday in which guerrillas killed a total of 35 soldiers, according to the state-run Philippine News Agency. In both cases, the government was reported to have launched large operations in retaliation.

In her second major policy speech since coming to power in a popularly backed military revolt in February, Aquino appealed to the communists to recognize that with president Ferdinand Marcos gone, they no longer enjoy an advantage over the government in the people's eyes.

Today's speech repeated key points raised in a March 22 address by Aquino at the Philippines Military Academy in which she warned that a "reformed and reinvigorated" armed forces would pursue those failing to answer her call for national reconciliation.

In her remarks today, Aquino offered the communists an "honorable peace." She did not use the word "surrender," but that is clearly what she is asking for. Officials said they hoped insurgents would turn in their arms, in return for which they would get amnesty and be reintegrated into society.

The communist New People's Army is estimated to have about 15,000 armed guerrillas in the field and many times that number of sympathizers. Bringing the insurgency under control is viewed by the Aquino government as one of its most important tasks.

Government forces have ceased most offensive operations since the change of government, but the communists continue to attack in some areas, officials say.

On Friday, an insurgent land mine and ambush killed 21 soldiers in Albay Province, 200 miles southeast of Manila. Yesterday, 14 more were reported killed when guerrillas opened fired on a three-truck convoy in Cagayan Province, 200 miles north of the capital.

In today's speech, a commencement address at the University of the Philippines, Aquino said that attacks on government forces would not, for the time being, be taken as rejection of the offer for talks. Rather, they would be seen as a sign that "the message of peace has not filtered down to all combatants." But she said she could not stand idly by for long.

"Under the Marcos regime, the balance was in the communists' favor," she said. "The people had distanced themselves from a government they feared and despised. They gave it neither cooperation in its spurious programs nor intelligence about the movements of the insurgents."

The communists sought to use these sentiments to create armed revolution, she said. But "the people took another route to freedom and they arrived without bloodshed and without tears," she said, referring to the street demonstrations that helped oust Marcos.

"I have no illusions that peace will come easily," she said. "For the communist true believer, the road to victory bristles with arms and resounds with combat."

The communists have signaled they are willing to talk. But in a recent interview with Filipino journalists, a senior insurgent scoffed at the idea of surrender and indicated that he did not see any major difference between the Marcos and Aquino governments.

Aquino said she would soon make a formal call for a cease-fire with a set and unextendable time period, during which negotiations for the "reassimilation" of insurgents would take place. After that, insurgents who remained in the field would face the full force of the armed forces again.

Aquino said she would deal only with top leaders of the Philippines Communist Party in negotiations. She warned that if the talks failed, "it will not be the old, dispirited army of Marcos that the insurgents will face."