A US federal judge has turned down a request from giant software firm Microsoft to throw out the case brought by nine US states who are pressing for tougher anti-trust penalties against it.

Microsoft last year reached an out-of-court settlement of the anti-trust case brought against it by the US Justice Department and 18 US states.

But nine of those states refused to sign up to the deal, objecting that the penalties against Microsoft were not strong enough.

Judge Colleen Kollar-Kotelly, who must decide on the adequacy of the penalties, dismissed Microsoft's argument that the dissenting states had no authority to bring their own case.

'Finish line'

"The court cannot now revisit the issue of jurisdiction," the judge said.

However, she said, Microsoft's request had "not passed unnoticed".

She said the court must presume that the issues Microsoft had raised had already been dealt with by the appeal court when it upheld the ruling that Microsoft was guilty of abusing its position.

"Now we can almost see the finish line in this case," said Tom Miller, Attorney General of Iowa, one of the nine states.

Judge Kollar-Kotelly said the final closing arguments in the case would be heard on 19 June.

"While we had hoped for a different outcome on this particular motion, we did raise some important constitutional and policy issues with the court," said Microsoft spokesman Jim Desler.

Open Windows

During the case, lawyers for the nine states have urged the judge to ensure a settlement that "create(s) fertile ground for competition".

Microsoft's lawyers have countered that the solutions demanded by the nine states would be "devastating" for the company.

The states want Microsoft to alter its Windows operating system - which sits on the desktops of most of the world's PCs - to create a modular version that would allow other software firms to add on their products.

Microsoft's lawyers have said these solutions would be impossible to implement.