Norwegian web browser developer Opera Software is behind a complaint that could lead Microsoft into another conflict with the European Union.

Opera has filed a complaint with the EU, claiming that Microsoft is abusing its position by tying Internet Explorer to Windows, and by not following web standards. It asks that the European Commission unbundle IE from Windows or package other browsers on the Windows desktop. It also asks the EC to force Microsoft to follow open standards.

"We are filing this complaint on behalf of all consumers who are tired of having a monopolist make choices for them," said Jon von Tetzchner, chief executive of Opera in a statement.

Demands for Microsoft not to abuse the dominant position that Windows and Office give it are nothing new of course, but calls for Microsoft to adhere to standards or face legal penalties add an interesting twist.

Microsoft supporters will no doubt point to Opera’s failure to establish itself as a big player in the browser space as the motivation for complaint. The Hitslink ranking system gives Opera less than one per cent of browser market share, compared to five per cent for Safari, 16 per cent for the fast-growing Firefox, and 77 per cent for IE.

In the late 1990s, Netscape and Microsoft frequently clashed over which company best observed W3C standards in their respective browsers. Microsoft’s standard argument is that it can “embrace and extend”, that is, take standards and add value through its own innovation. Critics say that because of its huge power, Microsoft can effectively break standards and force others to follow its lead.