The Reagan administration is pressing for multilateral negotiations aimed at increasing American exports of services as a way of improving the nation's economy, special trade representative Bill Brock has announced.

"Services trade is the frontier for expansion of export sales," Brock said in a statement to the Organization for Economic Cooperation and Development and released by his office yesterday. "Aggressive cultivation of foreign markets by U.S. service industries is as critical to our economic recovery as is increased export of goods."

Nations do not have the same orderly agreements on trade in services -- such as banking, accounting, communications and insurance -- as they have for trade in goods. If governments don't extend rules to the services area "intergovernmental tensions can be expected to increase and the multilateral system for economic cooperation in other areas could be weakened," Brock said. Trade in services is estimated to exceed $35 billion a year.

"For the most part . . . governments must rely on bilateral contracts on a case-by-case basis to resolve individual trade problems," the statement said.

Brock also noted "a disturbing trend" toward restrictions in some services areas. "This trend is emerging at a time when there are strong protectionist pressures affecting trade in goods."

The statement also said trade in services can be as beneficial as trade in goods and that each can stimulate growth of the other. Some service sectors, such as data processing and telecommunications, are particularly important in the export business and "will be one of the major sources of increased productivity in our economies over the coming decade," the statement added.

The Cabinet-level Trade Policy committee recently approved a plan for service industries to become more aggressive in marketing products overseas. The five-point program proposes:

Using existing bilateral arrangements with other governments to resolve some trade problems.

Including services in a review of "export disincentives," such as tax laws or regulations that tend to curb exports.

Preparing for future multilateral trade negotiations in services.

Reviewing U.S. laws related to achieving reciprocity for U.S. service industries.

Reviewing the adequacy of statistics on trade in services.