The European Committee for Interoperable Systems (ECIS) is attempting to delay the launch of Microsoft's Vista in Europe, claiming the operating system violates EU regulations.
Vista is scheduled for worldwide launch tomorrow (30 January).
ECIS, whose members comprise some of Microsoft's fiercest rivals in IBM, Nokia, Sun, RealNetworks, Oracle, Adobe and Red Hat, says complaints it raised last year about Vista are yet to be addressed by the European Commission.
In 2004, Microsoft was found guilty by the European Commission of anti-competitive behaviour, ordered to change its business practices in Europe, and fined 500-million Euros.
Microsoft has challenged this decision and is currently waiting for a ruling from the EU's Court of First Instance.
ECIS's challenge against Vista stems from the 2004 ruling.
In a statement issued on Friday, ECIS says: "Vista is the first step of Microsoft's strategy to extend its market dominance to the Internet", pointing out that the company's XAML markup language was "positioned to replace HTML."
HTML is currently the industry standard for publishing documents on the Internet.
XAML, ECIS continues, will be dependent on Windows and discriminatory against other operating systems such as Linux.
It also says that Microsoft's "open XML" platform file format – OOXML – which governs the way a document is formatted and stored, is designed to run seamlessly only on Microsoft Office.
"The end result will be the continued absence of any real consumer choice, years of waiting for Microsoft to improve – or even debug – its monopoly products and, of course, high prices," the statement says.
ECIS chairman, Simon Awde adds: "Microsoft has clearly chosen to ignore the fundamental principles of the Commission's March 2004 decision."
Reuters reports that Microsoft had no immediate comment on the statement and that it was unlikely the European Commission would take any drastic action.
"We are in the process of examining the complaint," a Commission spokesman told Reuters.