A U.N. staff member, held incommunicado since last August in a Polish prison, is to go on trial next Tuesday on charges of being a "talent spotter" for the CIA, officials of the Secretariat Staff Union learned yesterday.

Alicia Wesolowska, 35, was arrested in Warsaw on Aug. 13 as she visited her parents in Poland en route from New York to her new job as administrative assistant for the U.N. Development Program in Ulan Bator, Mongolia.

Since then, appeals on her behalf have been made by Secretary General Kurt Waldheim, Pope John Paul II, and numerous other international figures and organizations -- to no avail.

Until now, the Polish government refused to specifiy the charges against her beyond the general allegation of espionage for a Western government. It has also refused to allow U.N. legal representatives to visit her, a violation of her rights as a secretariat member traveling on a U.N. diplomatic passport.

Sunday night, however, a group established by her friends to press her case -- the Committee for the Release of Alicia Wesolowska -- heard from her court-appointed Polish lawyer that she is now scheduled to be tried in secret military proceedings beginning March 4.

The lawyer also reported that Wesolowska has experienced severe physical and psychological problems, said a committee respresentative, Lowell Flanders. Flanders suggested these problems "may indicate the results of torture."