A group of technology companies including IBM, Sun, Oracle and Nokia has joined the European Commission's case against Microsoft for anti-competitive practices.
The European Committee for Interoperable Systems (ECIS) group announced yesterday that it had been accepted as a complainant in the case along with Google and the Mozilla Foundation.
ECIS said it supports the EC's preliminary findings that Microsoft is violating EU anti-trust law by tying its Internet Explorer (IE) web browser to its Windows operating system.
The EC investigation followed a complaint by Norwegian browser developer and ECIS member, Opera Software, that other browsers cannot compete with IE because of its bundling with Windows.
In 2004, the EC was successful in its monopoly abuse case against Microsoft for linking its media player to Windows, fining the software-maker £497m.
ECIS said that by tying IE to Windows and making internet applications and content dependent on other proprietary technologies, Microsoft is seeking to become the gatekeeper to the internet.
The group's members want to curb Microsoft's dominance as key business, e-commerce, public service and social networking applications move to the internet.
ECIS spokesman Thomas Vinje said the case is important to ensure that browsers can compete on the merits and that consumers have a choice in the software they use to access the internet.
"Smaller, more innovative browser developers need a level playing field. That is why there is such broad support for the commission's preliminary findings of abuse," he said.
The EC issued a statement of objection to Microsoft in January and has given the software producer until the end of April to respond.