MANAGUA, Nicaragua (AP) _ A special commission will resume talks on reopening the Roman Catholic radio station as a step in advancing a new Central American peace plan, Nicaragua's ranking clergyman said Thursday.

The commission, made up of representatives of the Catholic Church and the leftist Sandinista government, was formed in September 1986 to ease tensions between the two sides.

It held six sessions on such issues as the government's closing of Radio Catolica and the expulsion of two high-ranking priests, but has not met since April 1.

Cardinal Miguel Obando y Bravo, the archbishop of Managua, said at a press conference that President Daniel Ortega told him he wanted the commission to resume its work.

Obando said the president wanted the commission to discuss the possibility of reopening Radio Catolica by Nov. 7, the peace plan's deadline for internal democratic reforms in Nicaragua and four other Central American countries.

Ortega and the presidents of El Salvador, Honduras, Costa Rica and Guatemala signed the peace plan on Aug. 7 in Guatemala City. The plan, aimed chiefly at ending civil wars in Nicaragua and El Salvador, calls for cease- fires, amnesty for rebels, internal democracy and free elections, and an end to foreign aid to insurgents.

Radio Catolica, which had been a platform for Obando and other clerics to criticize the Sandinistas, was shut down by the government Jan. 1, 1986, for failing to broadcast a speech by Ortega.

In July 1986 the government banished Monsignor Bismarck Carballo, who was Obando's spokesman and the radio station's director, and Bishop Pablo Antonio Vega, the archbishop of Chontales province. Both were accused of being disrespectful to the Sandinista revolution.

This week Ortega said that as a goodwill gesture the government was lifting the ban on the two bishops and on an Italian priest, the Rev. Benito Pitito, one of 10 foreign priests expelled in October 1984.

Obando said Carballo, who has been living in Miami, and Pitito have informed him they plan to return to Nicaragua.

Vega's plans are less clear. ''We have insisted that he should come back to Nicaragua but if he doesn't want to return that is his own decision,'' Obando said.