The Carter administration is studying a five-year plan that would move more than 5,400 Defense Department employes from Washington, the area's congressional delegations were told yesterday.

In a briefing late yesterday afternoon, Northern Virginia and Maryland congressmen were told by Deputy Secretary of Defense Charles W. Duncan Jr. that the Defense Department is considering moving 2 million square feet of office space from the Washington area.

No specific operations have yet been announced for relocation, congressional sources said.

Rep. Gladys Noon Spellman (D-Md.) said that Duncan told the group that more than 5,400 jobs, or three percent of the Defense work force in the area, could be affected by the move.

Another congressional source said that move could affect as many as 15,000 people.

Duncan decided in December to relocate the administrative space, which amounts to 10 percent of the Defense Department's office space in the Washington area, according to Perry J. Fliakas, assistant defense secretary for installations and housing. Plans for about half that space, which would effect the 5,400 employes, are already under study, Fliakas said.

One of the largest moves under consideration is transfer of the Army Military Personnel Center from Alexandria to Fort Benjamin Harrison, Ind. Nearly 3,000 jobs would be affected, almost 2,000 of them held by civilians.

Rep. Herbert Harris (D-Va.) said the meeting yesterday was requested by the delegations as "part of a series of things that we're doing to make sure that any transfers that are made are done on a cost-effective basis."

A similar 2 million square foot relocation was begun durin the Nixon administration and just recently was completed. The Defense Department has been under increasing pressure from the House Military Construction Subcommittee to decentralize military operations from the Washington area.

Rep. Spellman said the delegations are fearful that many of the military relocations are being planned because of political pressure rather than to save money.

"DOD seems to feel it has a mandate to move people out of the Washington area," she said. "We feel that any such move ought to be based on efficiency and cost effectiveness. Interestingly enough, the secretary said cost effectiveness is not one of the criteria."

Harris said Defense officials would rather not be pressured into the moves.

"Duncan was quite frank with us that there are these kinds of pressures and the department would rather make the decision on cost-effectiveness," he said.

The Military Construction Subcommittee has urged relocation in the past because of the high cost of living in the Washington area, especially housing costs. In its reports it also has cited the need to spread military operations to insure national defense.

Joy Silver, a legislative aide to Rep. Joseph L. Fisher (D-Va.) said the delegation was becoming increasingly concerned about a slow erosion of Defense Department jobs in the area.

"We've been fighting a lot of small fires, relocation by relocation, and we decided that was sort of a silly way to do it," she said.