The U.S. Postal Service said yesterday that Postmaster General William Bolger was unaware his mail was being given preferential treatment at a Northern Virginia post office.

And in a statement, Bolger himself declared: "I do not expect, do not deserve, nor will I tolerate any special treatment for my mail service." The postal service said certain department store advertisements addressed to Bolger were singled out for special treatment, but only to facilitate an investigation of mail delays.

Bolger's statement was in response to a story in yesterday's editions of The Washington Post containing allegations by several mail clerks at the Merrifield Post Office. The clerks said supervisors have routinely ordered them to stop work and sift through thousands of advertising circulars from a Washington department store to find the one addressed to Bolger. "Whenever a Hecht Co. ad comes in," said clerk Linda Lewis, "we stop everything and start sifting."

Clerks interviewed Tuesday said the search usually involved three or four persons, and took anywhere from a few minutes to an hour at least once every two weeks. Once the ad addressed to Bolger was found, clerks said, it was photocopied and placed in a carrier bag, assuring it of next-day delivery, although the rest of the Hecht's ads sometimes sat around for another day or two.

The postal service said yesterday it has been monitoring the Hecht Co. mailers at Merrifield since January, ever since the postmaster general "received a Hecht Co. advertisement at his home . . . advertised as a three day sale . . . received on the last day of that sale." Bolger, the postal service says, ordered an investigation. He got one, something the postal service calls a tracking survey, which is performed when "a pattern of mail delay is suspected."

According to postal service spokesman Walter E. Duka, advertisements addressed to Bolger were singled out when the Hecht's circulars came in because one supervisor was aware it was Bolger who had complained. "He says he did so," the postal service statement said, "because the mail arrived in alphabetical sequence and . . . it took a minute or two to pull these pieces out. This apparently led some clerks to jump to the conclusion . . . that Mr. Bolger wanted his mail expedited."

Clerks named at least four supervisors who had ordered the Hecht's hunt at one time or another, but the postal service said yesterday there was only one, Donald Pender. And Pender, reached at home late yesterday afternoon, wasn't sure if he stood along or not.

"I have thumbed through and looked for Mr. Bolger's circular," Pender said. "I really can't say whether other supervisors did. Sometimes I would see or hear the next day that they may have done that. But I would honestly not want to say. Sometimes," he continued, "that particular piece of mail would get out earlier than the rest of them. You could say the rest of it would sometimes sit for a day. You know, there's always mail at the post office."

At the Merrifield sorting room yesterday, clerks involved said they had been unaware of an investigation of mail delays. "It's been very quiet here today," said clerk Lewis. "Management hasn't said a word to us. They stayed away. They told the supervisors not to talk about it."