A Virginia State Bar hearing that could result in disbarment proceedings against Alexandria's former chief prosecutor, William L. Cowhig, has been postponed, it was announced yesterday.

Philip Hirshkop, Alexandria attorney and chairman of the 8th District Bar Grievance Committee, said the hearing into allegations of prosecutorial misconduct will be delayed until completion of a federal grand jury investigation of Cowhig and others.

Hirshkop's investigation into Cowhig's professional conduct grew out of an accusation made by a woman who said the prosecutor solicited a sexual favor from her in 1975 in exchange for a recommendation of leniency for her husband, a defendant in a drug case.

Last month, Cowhig was cleared of criminal wrongdoing by a special prosecutor who referred questions of possible professional miscondust to Hirshkop.

Cowhig's role in th city's bingo scandal is also under investigation by the Lawyer's committee. Cowhig was indicted last summer on three bingo-related felony charges.He was acquitted of two of those, including bribery, and resigned rather than face a third trial, on an illegal gambling charge.

Cowhig has repeatedly insisted he is innocent of wrongdoing.

The federal grand jury is known to be investigating Cowhig and Alexandria attorney James I. Burkhardt in connection with gambling, massage parlors and possible corruption of city officials. Federal prosecutors have said the investigation will continue for several months.