A federal judge here issued an arrest warrant today for an anti-Castro Cuban exile whose foreign travel has come under intense scrutiny by investigators probing the bombing death of former Chilean ambassador Orlando Letelier in Washington last fall.

The warrant was issued after Guillermo Novo, a top official of the Cuban Nationalist Movement in the U.S., failed to appear at a hearing on whether his parole on a 1974 explosives conviction should be revoked.

Assistant U.S. Attorney Eugene H. Propper, of the major crimes division of the federal prosecutor's office in Washington, said in court that Novo had traveled to Chile and Venezuela in violation of his parole. Citing that past travel, Propper asked U.S. District Judge George Barlow to issue the arrest warrant today for Novo when he failed to show up for the hearing.

Government investigators charge that Novo met in late 1974 in those two countries with Dr. Orlando Bosch, who heads a right-wing, anti-Castro umbrella organization known as CORU, the Coordination of United Revolutionary Organizations. Bosch currently is in custody in Venezuela, where he is charged in connection with the Oct. 6 crash of a Cuban airliner in which 73 persons died.

Novo's parole prohibits unapproved foreign travel.

Although federal investigators refuse to characterize Novo as a direct suspect in the Letelier bombing they reportedly feel he could be a key witness in their attempts to solve the case.

Another member of the Cuban Nationalist Movement. Jose Dionisio Suarez, has been in jail for the past six weeks in Washington for refusing to testify before the federal grand jury that is probing Letelier's death. Suarez refused to testify after being granted immunity from prosecution, saying he believed the probe is being used to harass the Cuban exile community in the U.S.

Although Guillermo Novo did not show up for his court appearance today, an attorney representing him did appear and asserted that Novo was not there because of a "misunderstanding." Novo's brother, Ignacio, also attended the hearing, but said he could not locate his brother this morning.

Both Novo brothers were charged in 1964 with firing a bazooka at the United Nations while Che Guevara was speaking there, but charges were dropped because they were not read their rights by the police officers who arrested them. Guillermo Novo's 1973 conviction was in connection with a conspiracy to bomb a Cuban ship.

Letelier and a coworker at the Institute for Policy Studies. Ronni K. Moffitt, were killed when a bomb explided in Letelier's car as they drive to work around Sheridan Circle NW in the Capital last September.

Informed sources have told The Washington Post in the past that federal investigators believe the assassination was carried out by anti-Castro Cubans directed by persons in Chile.