Naval investigators illegally seized and audited an award-winning civilian attorney's tax return and secretly made "sexual" movies of him with a woman shortly before his dismissal from a $52,500-a-year government job here, according to declarations in a federal court suit.

A spokesman for the Naval Ocean Systems Center (NOSC) in San Diego, where the events supposedly occurred, said it is Navy policy not to comment on current court cases.

The suit's allegations were disclosed as the House civil service subcommittee prepared to hold hearings on a bill granting new protections to more than 1 million "excepted service" government employes, including government attorneys.

The bill was inspired by the Navy's decision in October to dismiss attorney Stephen S. Stokwitz, 33, without giving him a reason, just after he received awards and was recommended for promotion.

A spokesman for Rep. Mervyn M. Dymally (D-Calif.), who introduced the bill, said Dymally is "very concerned that there be due process" in the Stokwitz case.

Current law allows government attorneys and other specialists who are hired without special examinations, as was Stokwitz, to be fired without cause and with no right of appeal.

Stokwitz, who had been NOSC general counsel, has sued for reinstatement and more than $1 million in damages.

He said the Navy's action, which officials have said grew out of an investigation of drug use and travel-voucher fraud, had put him more than $20,000 in debt and made it difficult to find a new job.

In declarations dated Thursday, Stokwitz and a private investigator, Mary Ellen Williams, said two unnamed individuals told them Stokwitz was filmed while off duty as investigators tried to build a case against him.

According to Stokwitz's declaration, the informants said he was followed to a restaurant, a hotel and a woman's house. "Several NOSC employes had seen the films taken of me by the NIS [Naval Investigative Service], and . . . these films were of a sexual nature, . . . 'hot' item to see," Stokwitz said he was told. A May 14 letter from Stokwitz attorney George C. Boisseau to Attorney General Edwin Meese III accused NOSC investigator Salvatore J. Lupo of seizing and auditing tax returns found in Stokwitz's office.

According to paragraphs in a naval investigative report released to Stokwitz by a federal judge over government objections, Lupo conducted an "inventory" of Stokwitz's office before an official search-and-seizure authorization. Lupo was reported to have said he "had seen" copies of Stokwitz's 1982 and 1983 tax returns at that time and "believed that [Stokwitz] may have understated his return" by not reporting a 1982 travel advance.

Boisseau, in the letter released by Stokwitz, told Meese he considers Lupo's actions to be felony violations of tax-return confidentiality laws.

Lupo declined comment.

In an interview, Stokwitz said, "I'm disgusted with the Navy for taking my tax returns, investigating my sex life and then illegally covering it up."

Stokwitz's declaration said the two people who told him and Williams of the filming "requested that their names not be disclosed at this time because they fear reprisal and retaliation at the hands of the Department of the Navy and the Naval Investigative Service." He said in an interview that one is a systems center employe and one a former Navy employe