BRASILIA, BRAZIL, JAN. 20 -- Brazil's governmental panel that makes policy on computers voted today to allow U.S. software maker Microsoft Corp. to sell its new DOS 3.3 operating system in Brazil, and officials said they hoped the move would prompt Washington to drop its threat to impose economic sanctions.

The National Informatics Council voted 16-6 to allow importation of the software after Finance Minister Mailson da Nobrega presented a study showing that there is no Brazilian-made equivalent of the software.

"The council decided that an earlier decision to bar importation of MS-DOS 3.2 was correct because at the time a local version called Sisne 3.2 existed," council spokesman Murilo Ramos said.

"But the minister {Nobrega} said that since no updated version existed, under the software law the MS-DOS 3.3 could be licensed for sale in Brazil," he said. DOS, which stands for disk operating system, is the basic software that runs International Business Machines Corp.'s personal computers and compatible models. IBM's new series of computers, however, also runs a more powerful operating system, called OS/2.

Approval means that Microsoft now may formally apply for the license, a process that takes a maximum of 120 days, according to the new software law approved by Congress in December.

But since the provisions of the new law have not yet been decided in detail by the executive branch -- a process that could take 60 to 120 days -- it was not yet clear whether the Microsoft request could eventually be rejected again if a Brazilian company registers an equivalent program in the meantime, Ramos said.

Science and Technology Minister Luiz Henrique said the decision was not specifically aimed at convincing the United States to lift $100 million in threatened tariffs on Brazilian exports, but he said it might help. "I think Brazil already has sent out a series of signals of good intentions," Henrique said. "Now I think it's time for the U.S. to do the same."

Brazil prohibits importation of minicomputers and microcomputers and some software and components under a law designed to allow the local industry to develop without fierce international competition. The U.S. computer industry estimates it lost $1.3 billion in sales between 1980 and 1984 as a result.