Law enforcement officials said they plan to ask a federal judge in Alexandria today for a court order giving them access to the patient records of Paul J. Peckar, a Fairfax County psychiatrist who was critically injured by a mail bomb Friday.

"The matter will be brought before a federal judge . . .to address the issue of whether or not federal authorities will be able to review patient files under very narrow and carefully crafted conditions," U.S. Attorney Henry E. Hudson said yesterday.

Although officials have said they had to consider Peckar's former patients among the possible suspects, investigators had so far honored the confidentiality of the patient-physician relationship and had not reviewed the doctor's records.

Law enforcement sources who asked not to be named said yesterday that a pair of psychiatrists would be closely involved in any review.

"The steps that the federal government is taking in the case are truly extraordinary, but we feel that the integrity of the files and the information they contain must be preserved and that any disclosure be done in a fashion calculated to protect the patient," said Hudson.

No federal statute governs client-professional relationships, but accepted ethical standards dictate that such relationships remain confidential.

Also yesterday, a reward of up to $50,000 was announced by the U.S. Postal Inspection Service for information leading to whoever mailed the bomb. Postal investigators asked that anyone with information call 636-2382.

Peckar, 50, of Riverside Road in Mount Vernon, was burned over 55 percent of his body and suffered severe abdominal injuries Friday when he opened a package investigators said contained a pipe bomb. The package was delivered by mail to his Mount Vernon office in the Sherwood Hall Medical Center on Sherwood Hall Lane.

Postal inspector D.J. Turner said yesterday that evidence from the bomb was being analyzed and the doctor's friends and colleagues were being questioned, but that no significant leads had emerged.

Fairfax Supervisor Gerald Hyland, a friend of the Peckar family who has acted as their attorney in the case, said the client records should not be released unless absolutely necessary.

"I have a written agreement with the assistant U.S. attorney that no patient file will be accessed or reviewed unless one of two things happens: one, that Mrs. Peckar gives her consent on behalf of her husband or, second, a court issues an order allowing review," Hyland said.

Hyland, who has met repeatedly this week with representatives of the U.S. Attorney's Office to determine how a review would be conducted, could not be reached last night to determine whether Pam Peckar would oppose inspection of her husband's records.

Joseph J. Polumbi, chairman of the Northern Virginia chapter of the Washington Psychiatric Society, said the standard of confidentiality of the patient-physician relationship should be flexible in "heinous" criminal cases, such as the bombing of Peckar's office. Polumbi said "some questionning or evaluation of some of {Peckar's} patients or cases might be valuable."

A spokesman for the burn center of Washington Hospital Center, where Peckar was taken soon after last week's bombing incident, said the psychiatrist was alert and receiving family visitors, but remained in critical condition.

A fund has been established to help pay expenses for Peckar and his family. Contributions can be sent to the Paul J. Peckar Fund, 2616 Sherwood Hall Lane, Suite 305, Alexandria, Va. 22306.