An Austrian exporting company and four Austrians were indicted yesterday in Alexandria for allegedly shipping $6.5 million worth of sensitive American high-technology equipment to the Soviet Union and East Bloc countries in violation of U.S. export laws.

Assistant U.S. Attorney Joseph J. Aronica said the government will seek the extradition of the four from Vienna, Austria, according to the 17-count indictment.

In a statement yesterday, Theodore Wu, deputy assistant secretary for enforcement in the Commerce Department, said the Austrian firm, Xennon GMBH, "was part of a carefully structured and executed international diversion network . . . [that] fed sophisticated military technology into the Soviet Union, East Germany, Poland and other Warsaw Pact countries."

The Commerce Department in recent years has increased efforts to stem the illegal export of high-technology equipment to communist countries. Officials maintain that one of the principal conduits for the illegal trade has been Austria, whose proximity to eastern Europe and relatively open trading policies have facilitated transfers.

Asked whether the indictments were a signal of Washington's intention to close the Austrian connection, Justice Department spokesman John Russell said: "We're notifying everyone we're cracking down. We've got more high-technology cases going on now than ever before."

Yesterday's indictment is the outgrowth of last year's prosecution of D. Frank Bazzarre, an Accokeek engineer who pleaded guilty to violating federal export laws by exporting microcircuits used for cruise missiles, antisubmarine warfare equipment and other high-tech items to Austria without a special Commerce Department license.

Bazzarre, who was sentenced to one year in prison and fined $110,000, agreed to cooperate with the government as part of his plea bargain, Aronica said. Bazzarre was not named as a defendant in yesterday's indictment, which charged that from July 1979 to June 1982 he conspired with Xennon's owner, Gerd Walther, Walther's wife Helga and two Xennon employes, Heinz Steinhardt and Traude Wallner, to export "$6.5 million worth of state-of-the-art technology to Western Europe for reexport to the Soviet Bloc."

The 48-page indictment outlined how Bazzarre, who headed the Alexandria-based firm of Technics Inc., ordered the equipment from U.S. companies under the pretext that it was for domestic use. He then would export the items to the Walthers, often through front companies in West Germany or Liechtenstein, without obtaining the required U.S. export licenses, according to the indictment.

The exports often were improperly labeled by Bazzarre so they would appear to customs officials as innocuous goods, the indictment said.

The Austrians would then ship the equipment to the Soviet Union and its allies, the indictment said. Each of the four faces up to 180 years in prison and millions of dollars in fines if convicted.

Austria and the United States have an extradition treaty. A spokesman for the Austrian Embassy said his country allows extradition if the alleged offense is also a crime in Austria.

Christian Prosl, minister counselor for economic affairs at the embassy, said Austria enacted a law in December 1984 requiring Austrian nationals who get import licenses to abide by restrictions imposed by the exporting country.