The Reagan administration has requested $73 million to improve two key U.S. military facilities in the Philippines, but some members of Congress are balking because of uncertainty that the current base agreement will be renewed after 1991.

The military installations subcommittee of the House Armed Services Committee voted to defer base improvements without a commitment from the new Philippine government of Corazon Aquino that U.S. forces can continue to operate there in the next decade.

The full committee was expected to accept that recommendation during a closed-door meeting yesterday.

Aquino has declined to discuss the bases, saying only that she would respect current agreements and keep options open after that. She also has raised the possibility of holding a referendum on the continued use of the bases, Clark Air Base and Subic Bay Naval Station, both on the northern island of Luzon.

The House Appropriations Committee, meanwhile, voted to cut the administration's request to $41 million, preferring to defer construction on a new $32 million runway at Clark but agreeing to fund other planned improvements.

"Our members felt that to not fund the projects would send the wrong signal to the Philippine government," an Appropriations committee staffer said. Preserving all but the runway money would allow living conditions to be improved at the bases but delay costly construction without a firm sign that the agreement will be renewed.

The appropriations measure is scheduled for a vote today by the full House. Even if it is approved as expected, the money cannot be spent without authorization by the Armed Services Commmitee.

The $41 million has been slated for maintenance on barracks, a data processing center, a child care center and a warehouse.

Administration officials said the new runway is needed because only one has been used for the last 40 years. One Defense Department official here described how flights into Clark had to circle the airfield while workers towed a disabled aircraft off the runway.

The request for maintenance money reflects the administration's public, official confidence that the United States can renegotiate rights to the bases regarded as strategically vital.