The Justice Department is investigating alleged problems at the Northern Virginia Training Center, a 285-bed institution in Fairfax County for severely retarded people.

A department spokesman confirmed the investigation yesterday but said she could not specify the nature or source of complaints that prompted it.

The probe is being undertaken under the Civil Rights of Institutionalized Persons Act, which allows federal officials to investigate state institutions for suspected deficiencies, including physical abuse of residents, overmedication, poor medical care, fire safety lapses or failure to provide proper training or education.

Training center Director David Lawson said state officials believe it is the first time such an investigation has been undertaken at a facility that has been certified by both Medicaid and the Accreditation Council on Services for People with Developmental Disabilities.

"We believe the residents of NVTC receive excellent care and training, and this belief has been reaffirmed repeatedly by other agencies in outside reviews," Lawson said in a statement, adding that center officials are confident of a favorable outcome.

Citing "the possibility of litigation" stemming from the probe, however, Lawson said center staff members are being asked not to discuss it.

Since the law was enacted a decade ago, the Justice Department has conducted 106 investigations at facilities across the country, including jails, prisons and institutions for the mentally ill and retarded, according to department figures. Once an investigation is finished, it often is settled with a consent decree by which officials agree to correct certain conditions. Twenty consent decrees are outstanding as a result of the department's investigations.

While federal investigators have not told state officials what they are looking into at the center, the period under review is June 1989 to the present, Lawson said. Justice Department lawyers and consultants are scheduled to inspect the facility Monday and Tuesday.

Parents of children living at the center have confidence in the facility and are concerned that the institution is being unfairly targeted, said Michael Pawlukiewicz, president of the Parents and Associates of Northern Virginia Training Center.

"I don't believe there are any civil rights violations there. If anything, it's a model," said Pawlukiewicz, whose son is a resident. "I think these guys {the Justice Department} are on a fishing expedition."

The center, on 82 acres off Braddock Road, serves profoundly mentally retarded people who often have physical handicaps and behavior problems as well. The center tries to train them in basic living skills and job skills, when possible.

While advocates and state officials consider the center one of their better facilities, it has had some serious problems in recent years. An undercover police investigation in 1986 led to allegations of physical abuse of more than 20 residents on one unit. Two staff members were fired as a result of the allegations, though they were never prosecuted, in part because the nonverbal victims could not testify.

Last summer, the center was notified that it was out of compliance with Medicaid standards and stood to lose $7.5 million in federal funds if certain deficiencies were not corrected. The facility passed a re-inspection and did not lose its Medicaid certification.