The Navy's plan to lease and perhaps buy more than 2.5 million square feet of office space in Northern Virginia has stalled amid tough congressional criticism about the proposal's price and location.

Leasing costs are estimated to run $1.4 billion over 20 years. Questions also have been raised about why the Navy has restricted its search to Northern Virginia.

"I can guarantee you we can purchase office space, purchase it for a third of this cost at least, in other areas of the country," Rep. Dennis M. Hertel (D-Mich.) said at a hearing on the issue last month before the House subcommittee on Military Installations and Facilities.

Another member of the subcommittee, Rep. Lynn Martin (R-Ill.), questioned why other sites in the Washington area, such as Anacostia, were not considered. She criticized putting "more money in Northern Virginia, which is already choking on federal funds."

The subcommittee deferred consideration of the request by the Navy and General Services Administration for permission to invite formal bids from developers. No new hearing date has been set.

The Navy has about 17,000 employees in leased office space in Crystal City and several hundred workers in Alexandria. The leases, which were signed starting in 1969, are expiring and the Navy proposes to consolidate its operations in more modern, spacious facilities.

The GSA, the federal government's real estate agent, solicited expressions of interest from developers last fall for a Northern Virginia site within a mile of the Capital Beltway and close to a Metro station and the Pentagon.

More than a dozen responses were received, said Keith E. Eastin, principal deputy assistant secretary for Navy shipbuilding and logistics.

Developers have proposed two sites in Crystal City and several along Eisenhower Avenue in Alexandria. Among those responding were the Navy's current landlords, a group that includes the Charles E. Smith Cos.

Eastin said yesterday that he also expects the Smith Cos. to submit another proposal to develop a site north of Crystal City now occupied by a cement plant.

The GSA had planned to award the new leases by this fall, but Eastin said that may be delayed now.

He said the Navy was considering only Northern Virginia because it wanted to minimize the hardship for its 17,000 employees, about three-fourths of whom live within five miles of Alexandria. An out-of-state move would mean hefty moving costs and the loss of senior workers who might not want to move.

The Virginia congressional delegation has fought hard to prevent a Navy move out of the state.

Proximity to the Pentagon also is important, said Eastin. Personnel travel between the Crystal City site and the Pentagon constantly. "Nothing beats being there where you can have some candid interchange," he said.

Even if the Navy stays in its current leased space in Crystal City, it might have to move temporarily because "the buildings are worn out" and need to be rehabilitated, he said.