The CIA's Central America task force chief, said to have ordered a field agent to continue arranging weapons drops for the Nicaraguan contras during the ban on U.S. military aid, received one of the agency's largest pay bonuses, according to intelligence sources.

The late William J. Casey, then director of central intelligence, awarded the bonus, which one source said was $20,000, to the covert officer, Alan Fiers. It was made last year under a federal program of awards to officials for meritorious and distinguished service.

Casey appointed Fiers to head the agency's Central America task force in September 1984, after Fiers had served as the Central Intelligence Agency's station chief in Riyadh, Saudi Arabia, according to the sources, who asked not to be identified.

Attempts to contact Fiers were not successful. CIA spokeswoman Sharon Foster said the agency does not comment on covert officers and that bonuses in the CIA, unlike those granted by most other government agencies, are not matters of public record.

The CIA director determines such bonuses, she said. In Fiers' case, it apparently would have amounted to a one-time pay increase of about 30 percent. The agency spokeswoman said someone of Fiers' rank and position typically is a senior-level officer making $54,000 to $68,000 a year.

Fiers' superior and CIA chief of clandestine operations, deputy director Clair George, received a bonus of a lesser amount, an intelligence source said.

A congressional report released Wednesday said the average bonus to senior government executives was $6,453, through a program for the rest of the federal government parallel to the CIA's awards. The report covered 1983 through 1986.

Fiers and George are among several CIA officials who have come under scrutiny by the congressional Iran-contra investigating committees and the office of independent counsel Lawrence E. Walsh.

The former CIA station chief in Costa Rica, known by the pseudonym Tomas Castillo, suspended from his job and recently reinstated to active duty, testified under oath that he told Fiers and Fiers' superior, chief of the agency's Latin America division, of his work in aiding the contras.

Castillo aided the weapons flow to the contras by passing information to contra leaders and Americans to assist contra air drops.