A group of five U.S. states and the District of Columbia today asked a judge to extend the terms of Microsoft's antitrust oversight agreement through 2012, in an effort to restrain possible monopolistic behavior.

The terms of the consent decree were set in 2002 after a ruling declared that Microsoft abused its power in the operating system and web browser markets. A group of states led by New York believe that the settlement has been effective and, with some exceptions, should expire in November as scheduled. However, an opposition group led by California, argue that an extension is needed to monitor Microsoft's practices with its new Vista operating system.

But the judge seems likely to lift the oversight, as she said the company is on course to satisfy all the terms of the oversight provisions. The California group now has to file a written proposal by October 15 laying out the terms and rationale behind the extension as well as proving that Microsoft has engaged in willful and systematic violations of the decree. Meanwhile, Microsoft is preparing to hear the outcome of its appeal of the European Commission's antitrust ruling against the company next Monday.