Microsoft will stop developing versions of its Internet Explorer browser software for Macintosh computers, saying that its own Safari browser is all that Apple users need.

The software company will no longer develop IE as an independent package, only as part of its Windows operating system. "Browsers are now a generally established piece of the OS and it doesn't make sense to keep developing them separately," said Microsoft UK desktop marketing manager Neil Laver.

Microsoft's development of IE for Apple's computers was driven by a five-year agreement that has now lapsed, Laver said.

Microsoft's OS and browser are very closely coupled, and now that Apple has developed its own browser there's no reason for Microsoft to continue development, he said.

The decision will cause concern for Mac owners who use IE to access sites that cannot be viewed in other browsers. Many site builders develop purely for IE as it is the dominant browser worldwide.

Microsoft will keep producing a version of its Office suite for Macs and its Virtual PC for Mac, Laver said. "We will definitely continue to support internet standards," he said.

But Rob Enderle, an analyst with Forrester Research, is not convinced Office development will go on. "With this decision we may be seeing the first steps to pulling out of the Mac platform altogether," he said.

Apple was not available for comment.