The Reagan administration will present Congress next week a revised Export Administration Act that attempts to encourage the sale of American high-tech products overseas without providing the Soviets with militarily useful technology, Commerce Undersecretary Lionel H. Olmer said yesterday.

Olmer told a National Press Club luncheon that the administration has solved "98.5 percent" of the issues involved in revision of the law, which expires in October, and he hopes the rest will be nailed down by next Thursday for presentation to Congress.

Olmer declined to give details of the administration's proposal, which will join at least three other bills on the issue on Capitol Hill.

The Export Administration Act, which is administered by the Commerce Department, has been used to control the export of a variety of American goods for reasons of foreign policy. President Reagan used the law to stop U.S. companies and their foreign subsidiaries from working on the Soviet natural gas pipeline. It also was used to halt grain shipments to the Soviets after their invasion of Afghanistan and to control high-tech exports to Cuba, Libya, Iraq and South Africa.

The process of drafting revisions for the law has turned into a tug of war between hard-line administration officials, such as Assistant Defense Secretary Richard Perle, who told Congress that a lack of export controls on technology saved the Soviets million of dollars in research and development costs, and Commerce Department officials, who want to increase exports to aid economic recovery.

The "conflict," Olmer said, lies between "permitting virtually unimpeded exchange of technology within the free world and at the same time controlling leakage to the Eastern bloc."

He said, for example, that allies such as Japan are vulnerable to the theft of American high technology that they buy. "Japan as a technological giant and leader in a number of different areas must be understood to be a prime target of Soviet intelligence," the Commerce undersecretary said.

A "substantial amount" of U.S. high-tech information has gone to the Soviet Union this way, Olmer said, though he declined to estimate its economic or strategic value.

He said the administration is working with U.S. industries to develop a "military-critical technologies list" that would "lighten the burden on business without compromising our security." The idea is to define "the truly strategic" by controlling the know-how needed to make essential military material and the "limited list of commodities which are keystones to the manufacturing process," Olmer said.

"The list we have been using on controlled commodities has become almost unmanageable," he said.

The administration is also studying ways to make it easier for American companies to transfer technology to their foreign subsidiaries, which he described as "a regulatory Gold Card" that would place extra responsibility on the U.S. company to make sure the technology "remains in house."

The new law also seeks closer cooperation with allies to keep them from leaking strategic materials and technology to the Soviets.