MANAGUA, NICARAGUA, JAN. 19 -- The Sandinista government today officially ended a state of emergency that had been in effect for almost six years and abolished special political tribunals.

Foreign Minister Miguel d'Escoto put an end to three days of confusion about the status of the emergency restrictions by reading a communique to a gathering of diplomats.

President Daniel Ortega had announced that he planned to lift the state of emergency, which had suspended many constitutional guarantees, during a Central American summit in Costa Rica last week.

The Sandinista concessions, which were made to comply with a regional peace plan, came amid intense jockeying by both sides in the Nicaraguan conflict in anticipation of the Feb. 3 and 4 vote in the U.S. Congress on aid to the rebels, known as contras.

{The White House announced Tuesday that President Reagan had authorized resumption of airdrops of previously stockpiled weapons and ammunition to the anti-Sandinista rebels. Details on Page A14.}

In Miami, Nicaraguan rebel leaders, responding to a Sandinista government's proposal for direct cease-fire negotiations, agreed today to participate in the talks but said they will meet first separately with the mediator, Cardinal Miguel Obando y Bravo.

The first meeting between Obando and the six top directors of the Nicaraguan Resistance, the rebel alliance, is to take place Thursday in San Jose, Costa Rica, five of the six directors announced at a press conference. Obando's mediation also has been accepted by the Sandinistas.

The political leaders of the contras, said they are willing to begin the cease-fire talks after that meeting, but they did not specify when. The contras have been demanding to meet with Obando since early January, saying they want an opportunity to explain their cease-fire position fully.

Many doubts remained in Managua about what the end to the emergency will mean.

The emergency decrees sharply limited political meetings and public demonstrations and gave government security police ample powers to detain and hold anyone suspected of collaborating with the contras.

The Popular Anti-Somocista Tribunals were frequently criticized by human rights groups as highly arbitrary. Eugene Hasenfus, the American flier who was shot down over Nicaragua Oct. 5, 1986, was tried in those courts, sentenced to 30 years and later pardoned.

Another downed and jailed American flier, James Denby, whose case had been brought before a special tribunal, will now be tried by the regular courts, government officials said.

The restoration of all constitutional rights should mean that more than 1,000 Nicaraguans now being held in State Security detention centers, in some cases incommunicado, awaiting trials in the special tribunals, will have to be tried expeditiously or released.

Despite the end of the emergency, State Security police briefly detained five opposition activists for questioning as they returned this morning to Nicaragua at Managua's international airport.

They included Carlos Huembes, head of the Democratic Coordinating Group, the opposition coalition.

Their names appeared on a list published last week by the Interior Ministry, which runs the State Security police, after they participated in a meeting in Guatemala with some Nicaraguan Resistance leaders. They were accused of collaborating with the contras in a CIA-sponsored plot.

The ministry said they were released late this afternoon, but they avoided speaking to the press.

The contras, meeting in Miami, accused the government of bargaining in bad faith in two rounds of indirect cease-fire negotiations they have held up to now. They charged that Ortega lifted the state of emergency solely to sway the opinion of U.S. legislators.

But the contras also made it clear that they are in no hurry to push toward a cease-fire before the congressional vote.

They called on the Sandinistas to enter into three-way talks about political reform involving both the contras and the political opposition, to be held at the same time as the cease-fire dialogue. But they said they will attend the cease-fire talks whether or not the parallel talks occur.

The Nicaraguan Resistance named two non-Nicaraguan advisers to its cease-fire negotiating commission: Gonzalo Facio, former foreign minister of Costa Rica, and Adm. Ramon Jimenez, former foreign minister of the Dominican Republic. In 1979 Jimenez presided over a session of the Organization of American States that voted in favor of the ouster of the late Nicaraguan dictator Anastasio Somoza.

The Sandinista government is unlikely to accept the three-way talks. Contra directors Pedro Joaquin Chamorro and Alfredo Cesar said today they are moving out of Costa Rica, probably to Miami, to comply with an edict by President Oscar Arias, author of the regional peace plan, demanding that they either renounce armed warfare or leave his neutral nation. But Alfonso Robelo, a third director ordered out by Arias, said he has not yet decided what to do. His Costa Rican wife is expecting a child this month. Robelo, who has extensive business interests in Costa Rica, said he is considering the possibility of resigning as a Nicaraguan Resistance director or even of going back to Nicaragua.