Major Soviet advances in developing quiet submarines leave "no room for complacency" and mean the United States should increase spending for submarine design, a panel of experts say.

"The free lunch is nearly over with the introduction of quiet Soviet submarines," Dr. William J. Perry, a former Pentagon undersecretary for research and development, told two subcommittees of the House Armed Services Committee.After years of making noisy subs, the Soviets have begun to build them quiet enough to present "a major technological challenge with profound national security implications," said the 10-member panel of specialists in submarine warfare.

The panel urged Congress to spend more on research and development on submarine design and to develop a successor to the Seawolf submarine.

According to subcommittee staff members, the Bush administration's defense budget proposals call for an increase in funds for anti-submarine warfare over the next two years but a decrease after that. Dollar amounts were not immediately available.

"The Soviet program is impressive. There is no room for complacency," Perry said. "The United States still has the lead but the Soviet submarines are quiet enough to give our anti-submarine warfare a real problem."

Another expert, Dr. Harold Rosenbaum, told the subcommittees that the United

States "cannot afford a Mexican standoff in submarine technology. We can't afford submarines so quiet and so good that we can't stop them."

Rep. Les Aspin, D-Wis., chairman of the House Armed Services Committee, named the panel last year and on Monday released the results of its work.

"This development could bring a sea change in sea warfare - and not one to our benefit," Aspin said in releasing the report before hearings by the research and development and the seapower and strategic and critical materials subcommittees.