DES MOINES, Iowa — Attorneys representing 23 states involved in a class-action lawsuit against Microsoft Corp. have filed a lawsuit over attorney fees against the Iowa lawyer who spearheaded a $179.5 million settlement.

Roxanne Conlin of Des Moines negotiated the 2007 settlement that included $75 million in attorney fees that she split with attorney Richard Hagstrom and the Zelle Hoffmann law firm of Minneapolis.

Conlin and Hagstrom filed the lawsuit against Microsoft, which is based in Redmond, Wash., claiming the company engaged in anti-competitive conduct that caused consumers to pay more for software between 1994 and 2006. The settlement was announced in August 2007.

The lawsuit claims that attorneys in 23 states provided advice, pleadings, participation and prosecution in the class-action case in their states, and in the Iowa case against Microsoft.

The group formed The Microsoft Litigation Consortium. The lawsuit filed last month in Polk County District Court said the group signed an agreement with Conlin that called for the consortium to receive 20 percent of attorney fees awarded in the case. It also said disputes were to be resolved through arbitration.

“The attorney fees awarded to (Conlin) at the conclusion of litigation were not shared in violation of the agreement,” the lawsuit states.

The lawsuit said that Conlin has refused to comply with the agreement and that “on multiple occasions (the consortium) has requested that (Conlin) comply with the agreement and arbitrate the dispute regarding the fees.”

Thomas Hanson, the Des Moines attorney who filed the lawsuit, said it is seeking a court order to force Conlin to enter into arbitration.