The Reagan administration, trying to salvage its proposal to tighten controls over East-West trade, asserted yesterday that a version of its bill reported out by the House Foreign Affairs Committee "strikes at the core" of efforts to stem the "illegal diversion" of high technology to the Soviet bloc.

Assistant Defense Secretary Richard Perle told the friendly forum of the House Armed Services Committee that the Foreign Affairs Committee bill extending the Export Administration Act represents "the triumph of a few special interests at the expense and well-being of the whole."

In two hours of testimony, Perle detailed four Soviet weapons systems that he said benefited from either stolen or purchased American technology that saves Moscow's military planners "perhaps billions of dollars in research and development . . . by implementing proven designs developed by the West."

"Virtually every new Soviet weapons system is produced, at least in part, with the aid of modern technology acquired from the West. Indeed, the Soviets have become arrogant in their reliance on Western technological solutions for their military problems," Perle said.

Although the extension of the Export Administration Act falls within the jurisdiction of the House Foreign Affairs Committee, a special panel of Armed Services moved in, reportedly at the urging of the Pentagon, in an effort to build a record that would cause the House to stiffen the legislation.

The Foreign Affairs Committee took the position that the administration bill irritates the United States' Western allies and impedes efforts within the alliance to place effective curbs on trade in high technology with the East bloc, while at the same time hurting American exports.

Commerce Undersecretary Lionel H. Olmer, however, told the Armed Services Committee that the administration bill balances "two vital goals of stemming harmful technology transfers while minimizing unnecessary, adverse impacts on legitimate trade."

He too said parts of the House bill "undercut" administration efforts to keep the Soviet bloc from getting Western high technology. He objected specifically to provisions that eliminate requirements for licenses of exports to Western allies; end controls on products to specific countries after the first year of approval; and cut export sanctions on a product after six months if the banned goods are available elsewhere and the other suppliers refuse to join in the export ban.

Questioning by the committee uncovered differences between the Defense and Commerce departments in their outlook on export controls, but both Perle and Olmer said these were due to the different constituences these departments represent.