The 32-year-old son of Maryland's acting governor, Blair Lee III, is using an office at the statehouse here as a base for helping to coordinate his father's gubernatorial campaign.

Blair Lee IV, who left his Virginia cattle farm inn June to join his father's campaign, has had exclusive use of an otherwise empty ground floor office - complete with telephone for the past 10 days.

The younger Lee defended his use of the office by saying that many of the political activities he performs on behalf of his father overlap with the acting governor's official duties.

"If I go in his place to speak to some group, is that a campaign stop or an official visit?" he asked. "It's a gray area. But I don't think it's a matter for Barney Skolnik (the U.S. prosecutor.)

The elder Lee, who is attending the annual meeting of Maryland's Chamber of Commerce in BedfordSprings, Pa., expressed surprise when told his son was using the office across the hall from Statehouse pressroom.

"Is he dug in?" Lee asked an inquiring reporter.

"If he is, he is, "the acting governor continued."The next time I'd hope he'd find a place that's not across the hall from the pressoom."

It has not been uncommon at the early stages of Maryland political campaigns for candidates who hold official positions to make use of state facilities and personnel for political purposes, thus prompting questions about the propriety of their actions, p One of Lee's competitors for the Democratic nomination for governor, Maryland Attorney General Francis B. Burch, was the object of news accounts last spring retailing how two of his deputies had asked the 100 lawyers in Burch's office to sell tickets to a fund-raiser for his campaign.

Gov. Marvin Mandel's staff aides, while drawing state salaries, performed important tasks in his past campaigns, raising frequent questions at Mandel's press conferences.

In an attempt to break with tradition, Acting Governor Lee pledged several weeks ago that he would not ask state employees to raise money or actively participate in his campaign.

The younger Lee had said last week, "I've got to get out of here (the office) pretty soon before a reporter starts asking questions."

He also said he plans to pay the state a rent of up to $350 a month when he moves his family into the Governor's Mansion to live with his parents.

Moving into the 54-room ornate mansion across from the Statehouse, he said, will provide him with immediate access to his father so that he can relay messages during the heat of the campaign.

Because he plans to do campaign work from the mansion, he said, it would only be proper to pay rent to the state consistent with Annapolis prices for a house large enough for his wife and 4-year-old son.

Lee said he decided to use the empty groundfloor office for campaign work at the suggestion of a Statehouse official who noticed the young man uncomfortably working in the outer office of his father's office.

He said he will remain there until his father opens a campaign office in Annapolis "not much longer."