The Reagan administration's program to reduce federal office space may be costing more to implement than the savings it is supposed to yield, according to officials with the Office of Management and Budget and the General Services Administration.

When the program began in October 1983, agencies were supposed to trim the 164 square feet that the average federal office employe had by 10 percent in fiscal 1984. By the end of fiscal 1986, the average work space was to be reduced further, to 135 square feet per employe.

So far, it hasn't met the schedule.

By the end of fiscal 1984, the average government worker had lost only two feet of office space, down to 162 square feet -- a drop of less than 2 percent.

In March, John Merck, OMB director of planning and communications management, told House Post Office and Civil Service Committee staffers that the program so far had cost more than it has saved.

In a subsequent interview, Merck said that the $1 billion the administration originally anticipated saving was "well beyond the actual achievements that we attained and that were possible. GSA did not have the clout to force agencies to reduce."

OMB spokesman Steven R. Tupper said the administration tried "to recover the savings and there were none. It costs something to manage the program." Tupper said some blame belongs to OMB, which in his view didn't move quickly enough to publish clear guidelines or give GSA a "big stick."

Both the program's costs and accomplishments, however, are in dispute. The Public Buildings Service says the effort has cut the average work space by four square feet, which represents an annual savings of $33.2 million, according to David Bibb, director of GSA's office of space management. But Jerald D. Fox, a senior aide to acting GSA administrator Dwight A. Ink disagreed. He said half of that annual savings is "due to bookkeeping changes that artificially reduced the space figures. The best number to use is a two-square-foot decline." Using those numbers, GSA would have saved approximately $16.6 million.

As for the program's cost, agencies spent $1.4 million to draw up plans for reducing space and $9.7 million to remodel when they were moved into smaller quarters.

A third component -- the cost of carrying vacant space until it can be sold or subleased -- also is in dispute. PBS Commissioner William F. Sullivan said the cost of carrying "vacant space was negligible . . . less than $100,000 I would say." But several other veteran GSA officials, who did not want to be identified, said the cost of carrying vacant space could run as high as $20 million a year.

James G. Whitlock, GSA Regional Public Buildings Commissioner, offered a different perspective: "You never have a situation where a block of space is given up and is out of the inventory immediately. You're always carrying it for some period of time."

OMB is working on regulations that would give it more control over the program. GSA's role would become an advisory one, OMB's Tupper said.

Roger Dierman, deputy associate administrator of GSA for administration, said the program has had success in disciplining federal agencies.

"It has linked, for the first time, the cost of managing real property and the budget process," Dierman said. "This will strengthen the commitment of the president to force agencies to give up what they don't need."