A lobby group backed by Nokia, Oracle and IBM has asked an EU court for permission to join the European Commission in its antitrust battle with Microsoft.

The five-firm European Committee for Interoperable Systems (ECIS) said its request demonstrated there was still solid industry backing for the EU executive's crackdown on Microsoft, despite settlements with some opponents.

In a landmark ruling last year, the Commission found Microsoft abused the near-monopoly of its Windows computer operating system to crush competition.

It fined the world's biggest software maker nearly €500 million and ordered it to change its business practices.

Microsoft failed in its bid to delay the sanctions, which required it to sell a version of Windows without Windows Media Player and share software data with rivals.

However, the software giant is appealing the main ruling, even as it puts in place the changes ordered by the European Commission.

The ECIS technology industry group, which also includes software firms Red Hat and RealNetworks, has asked to intervene on the EU executive's side against Microsoft's appeal at the European Court of First Instance.

Thomas Vinje, a lawyer with Clifford Chance in Brussels who represents the committee, said it undermined Microsoft's claims that technology firms did not back the Commission's ruling.

"Microsoft, in the wake of buying off several of the Commission's supporters, has been saying that the Commission stands naked, that is has little or no industry support for its case," Mr Vinje said. "I think that this resoundingly demonstrates that is not true."

However, the committee's application to intervene may be rejected because it missed a December court deadline, Mr Vinje said.