Allergy physician John Richard Stewart has been accused of billing federal and private health insurers for services that were not rendered or were performed unnecessarily.

In documents filed Wednesday in U.S. District Court, the 56-year-old doctor was indicted on 40 counts of mail fraud and making false statements stemming from his Holladay practice.The alleged scheme dates back to 1992 - a time when Stewart was on probation in a state case for defrauding the Utah Medicaid program by billing for nonexistent nasal examinations.

Stewart had pleaded no contest in 3rd District Court to the state charge. As a result, the conviction was held in abeyance for one year - until December 1993 - when it was dismissed after he completed probation. He has been barred since 1993 from participating in Medicaid or the federal Medicare program.

In the meantime, however, the doctor found another governmental health insurer, the Civilian Health and Medical Program of the Uniformed Services, which provides medical benefits to federal retirees.

Last week's indictment accuses Stewart of inflating his services and other illegal billing practices when his office staff submitted claims to CHAMPUS and four private insurers from 1992 to February 1997. The charges involve 21 patients.

Stewart could not be reached for comment. His office phone numbers have been disconnected.