Nicaraguan military aircraft bombed a boat carrying a Costa Rican Cabinet minister, as a border conflict between the Central American neighbors alternately sizzled and fizzled yesterday.

At the same time, Nicaragua lodged a formal protest against Cuba in the Organization of American States here for allegedly offering moral and material support to the leftist Nicaraguan querrilas who began the conflict two days ago.

According to a Nicaraguan official bombing and strafing of a boat carrying Costa Rican Public Security Minister Mario Charpentier was a "small incident" that did nothing more than "scare" Charpentier and an entourage of Costa Rican officials and reporters.

At the time fo the incident, Charpentier was traveling on the Frio River toward the Nicaraguan border to inspect Costa Rican troops sent there when the frontier between the two countries was closed Thursday.

The closure came after an attack on a Nicaraguan military encampment near the border bearly Thursday morning by an estimated 50 members of the Sandicista Front, a guerrila group that has fought the government of Nicaraguan President Gen. Anastasio Somoza since the early 1960s.

Nicaraguan officials said several members of the Nicaraguan National Guard were killed in the attack. Several guerrilas reportedly escaped into Costa Rica. Nicaraguan planes bombed the military outpost and the nearby Nicaraguan village of San Carlos Thursday and yesterday.

According to some news reports, the planes also bombed the Costa Rican border village of Los Chiles.

Thursday's attack was believed to be the first major Sandinista offensive since 1974, when a group of guerrilas broke into a party in Managua for the U.S. ambassador. Several people were killed, and the guerrilas took a number of hostages who were later released in exchange for a ransom, release of several imprisoned leftists and transportation for the guerrilas to Cuba.

Another guerrilla attack was also reported yesterday morning near the village of Ocotal, in northern Nicaragua. Nicaraguan officials said at least five National Guard soldiers were killed.

In the past several years, Nicaragua has repeatedly charged Cuba with aiding and abetting the Sandinistas, who take their name from a guerrilla leader who fought against U.S. occupation forces in Nicaragua in the 1930s. It charges that the guerrilas are trained and armed by the Cubans, who then arrange to transport them back into Nicaragua to launch terrorist attacks.

The Sandinistas are one of a number of guerrila groups from several Latin American nations with rightist governments who have found refuge in Cuba, and sometimes a launching pad for at least verbal attack, on their own countries.

The Nicaraguan complaint against Cuba will be discussed by the OAS Permanent Council, made up of ambassadors from its 24 member nations, at 3 p.m. today. Cuba, however, will not be represented. Although Cuba is still technically a member of the OAS, it has been barred from active participatin since 1962, when an OAS majority decided that the "Marxist idiology" espoused by Cuban leader Fidel Castro was not compatible with OAS international objectives.

While Costa Rica has protested yesterday's bombing, its relations with Nicaragua seem to be bearing up under the strain.

An element of tension remains, however, Nicaragua believes that some fo the Sandinistas, whose total number has been estimated at between 50 and 150 members, are allowed to live in Costa Rica with the knowledge of the Costa Rican government.