The Interior Department has called on the General Services Administration to withdraw a controversial proposal to sell the 50-acre Jones Point park in Alexandria for commercial development, a move that an Alexandria official says undermines the plan.

In a letter to the GSA, department property director R.W. Piasecki said the park is "an important historic and recreation resource" that is exempt from sale because it became part of the national park system in 1975.

Piasecki's statement was welcomed by the Alexandria city government, which last month strongly condemned the GSA proposal. "That reduces the chances of GSA going ahead with it," said city Planning Director Engin Artemel.

A month ago, as part of Reagan administration policy to sell surplus federal lands, GSA released a survey that concluded that "the highest and best use of the land at Jones Point may be residential development." It recommended sale, but the Interior Department letter recommends that the government hold onto the land.

"Jones Point Lighthouse and the District of Columbia Boundary Stone Number One, which was located by George Washington, are located on this property. In addition, there are historic remnants of a World War One shipyard," said the letter, dated July 25.

"Jones Point also serves as a natural area in an urban environment, offering a haven for wildlife in its woods and shoreline marsh. The park is of national importance in that it preserves an important part of the natural and historic shoreline of the Potomac River which forms a gateway to our nation's capital," the letter said.

Located north and south of the Virginia ramps to Woodrow Wilson Memorial Bridge, the land is owned by the federal government but maintained by the city of Alexandria, which is building two fishing piers there and recently opened a bicycle path that runs through the property.

City officials view Jones Point as crucial to long-term plans to transform the city's Potomac River waterfront into a string of parks and public facilities. Hearings are scheduled for this fall into Jones Point's further development as a park.

The Interior Department letter said the land was placed in the national park system by the National Capital Planning Commission in 1975 and could be sold only if Congress or the planning commission specifically authorized it. GSA had concluded earlier that the land was not part of the park system.

GSA official B. Michael O'Hara said yesterday that GSA attorneys are evaluating the land's legal status. If they conclude it is not in the park system, they will refer the matter to the Property Review Board, an executive branch body that settles property disputes between the GSA and other federal agencies, O'Hara said.