Opposition party leaders here predicted yesterday that there would be more violence today during nationwide municipal elections that President Anastasio Somoza has refused to cancel despite severe and increasing tension in this Central American country.

Somoza, looking somber, told his countrymen during a televised speech Friday night that, despite a 12-year-old general strike, increasing activity by armed guerrillas and growing opposition to his rule, he will not resign his office nor will he postphone the elections.

"No violence, no strike, nothing has kept us from continuing to enjoy our constitutional guarantees. One of these is going to the polls without fear and freely," Somoza said, adding that National Guardsmen will be out in force at polling places to protect Nicaraguans who come to vote.

But Fernando Zelaya Rojas, a member of the Nicaraguan congress and director of the opposition Conservative party, predicted that violence would occur at the polling places anyway. The Conservative Party issued a communique saying that it has "excused itself from any responsibility for anything that happens Sunday" during the elections.

Meanwhile, National Guard troops loyal to Somoza attacked housewives and children Friday night as they stood in front of their homes in Managua banging pots to demonstrate their opposition to the 45-year-old Somoza dynasty.

Tony Delgado Whalen, 38, a secretary with an American accounting firm in Managua, said guardsmen chased a group of children and teenagers into her house. She said the troops look several of the youngsters away, ransacked the house and threatened her 11-year-old daughter, who is deaf, with a gun."The kids weren't doing anything," she said.

In his speech Friday night, Somoza did not announce new emergency measures to deal with the deteriorating situation. But there appeared to be an increase in National Guard patrols throughtout the capital and in several provincial towns.

Troops, backed by helicopters and tanks, were reportedly heavily concentrated in Rivas and Granda, two towns captured Thursday night by members of the Sandinist National Liberation Front, a left-wing guerrilla group. A spokesman for the Somoza government said National Guard troops were able to push the guerrillas back into Costa Rica Friday morning. As many as 13 people were reported killed during the guerrilla raid.

Nicaragua has been turmoil since the Jan. 10 assassination of Pedro Joaquin Chamorro, a newspaper publisher and outspoken critic of the Somoza regime. Leaders of the general strike which has virtually paralyzed Nicaragua, have been demanding to know who was behind the assassination.