TOKYO (AP) _ Matsushita Electric Industrial Co. has been found by U.S. authorities to have infringed on a software copyright of International Business Machines Corp., a Matsushita spokesman said Tuesday.

The giant electric and electronic company has agreed to pay a penalty for illegally copying IBM's so-called BIOS in making its IBM-compatible personal computers exported to the U.S. and European markets. The BIOS, or basic input output system, controls the movement of data in and out of the computer.

The copyright infringement was discovered during a routine computer analysis by the U.S. Customs Service in Seattle, where the computers were imported, according to Steve Winston, a chief of duty assessment at the Seattle office.

The Matsushita spokesman refused to disclose the amount of penalty, but the Nihon Keizai Shimbun, a nationally circulated business daily, reported that Matsushita is paying roughly $1.9 million to $2.6 million to IBM.

The Japanese company will suspend exports of the computer, FX800, priced at $2,300 to $2,600, to the United States as well as to the European markets. The company also plans to retrieve most of the FX800s that have already been shipped, at least those that have not reached retail outlets, the spokesman said.

Besides the penalty, the spokesman said, IBM demanded that Matsushita allow inspection of its computer production facilities. However, he said, Matsushita is refusing the demand.

Matsushita, the manufacturer of National, Panasonic, Technics and Quasar brand products, supplies some components to IBM.

Company president Akio Tanii said the case was not as big a problem as others involving more sophisticated IBM software. ''I don't think this case will impede our friendly relationship with IBM in the future,'' he said.

IBM issued a statement saying the infringement issue with Matsushita had been resolved and ''we believe amiable relationships between the two companies will continue. The company added that it regards copyright infringement as a serious matter.'' IBM declined to comment on details of the agreement.