Baltimore developer Morton Sarubin has offered to buy most of Alexandria's 1,150 public housing units, move the tenants elsewhere, and then redevelop the land -- some of the city's most valuable acreage -- for commercial ventures.

The housing projects, the only public housing in the Virginia suburbs, are currently valued at at least $37 million by Alexandria officials and are said by some to be worth considerably more than that. One of the housing projects is located next to the Braddock Road Metro station in an area that is expected to undergo a dramatic transformation when the subway opens there next year.

Sarubin, who already is spending $80 million to rehabilitate the city's huge Shirley-Duke apartment complex, made his proposal as Alexandria officials are debating the future of the aging public housing units, scattered about the city at eight sites.

"I think it [Sarubin's offer] bears consideration," City Councilwoman Marlee Inman said. "I think we ought to consider any plan to stop the deterioration of the public housing projects and improve living conditions for residents," she said.

Sarubin made his proposal in a three-page letter to the council, and the city's semiindependent housing authority, which actually owns the projects. The proposal failed to spell out what Sarubin would do with the land, or how much he is willing to pay for the projects, which currently house 2,891 people.

Because Sarubin's proposal lacked detail, some area developers said yesterday it would be difficult to assess how profitable his venture could be. One Alexandria developer estimated that Sarubin could make as much as $4 million by building townhouses on the site near the Metro station. His margins could be even higher for buildings at the other housing sites where larger projects are permitted, the developer said.

Councilman Nelson E. Greene Sr. promised to fight the proposal. "I am strictly against it. The way it reads we [the city] would be quickly out of the public housing business. He (Sarubin) might build new public housing units for people, but a future council could cancel our commitment to them."

The city is obligated to maintain the public housing projects as long as the federally backed mortgages which financed them are in effect, Greene said. t"We would not have that guarantee with his proposal, which frightens me," said Greene.

The city government also is committed by a contract with the housing authority and its own laws to maintain at least 1,100 public housing units for low-income residents in the city. Since the federal mortgages on the projects, built shortly after World War II, have begun to expire, city officials have started debating whether to keep those projects in their current locations, or move the residents elsewhere and sell the sites for development.

Alexandria officials said that major legal problems lie ahead of Sarubin, even if the council endorses his plan. For one thing, six of the eight public housing projects still carry federal mortgages, some of which are not scheduled to expire until the year 2000. One official said he doubted that the mortgages could be paid off by Sarubin ahead of time, unless the incoming Reagan administration is willing to change federal procedures. "But he [Sarubin] is a high roller, maybe he can convince them," the official said.

Another problem would be finding housing for the public housing residents the plan would displace.City Manager Douglas Harman predicted that Sarubin "would probably have to rehabilitate some units on their existing sites. There just is very little vacant land available" in Alexandria, he said.

In Sarubin's proposal, tenants would be evicted from their homes only when new facilities were available for them. Sarubin's proposal claims he would make no profit on construction of housing for the displaced, but would profit from development of construction on the old housing sites.

The proposal, which will be discussed by the City Council Tuesday night, does not detail whether Sarubin would construct residential or commercial property on the land, or where he would get his financing.