HARRISBURG - Gov. Corbett's plan to overhaul Pennsylvania's Medicaid program is being mishandled and in less than 10 days could create serious medical problems for people who are cut off from crucial health care benefits, lawyers for the poor argued Monday in a court challenge.

The lawsuit, filed in federal court in Philadelphia, seeks to halt the diversion of Medicaid enrollees into new plans with limits designed for healthier adult Medicaid enrollees.

The Corbett administration disputed the allegations in the lawsuit.

The filing comes ahead of the Jan. 1 effective date for the administration's plan to restructure benefits in the health-care program that currently serves 1.1 million adults.

Including the expansion of Medicaid's guidelines under the 2010 federal law, Corbett's plan creates three benefit levels to replace the 14 currently in effect. Each Medicaid enrollee would be sorted into a benefit level based on his or her relative health and income.

But Community Legal Services of Philadelphia and the National Health Law Program said reductions in benefits designed for working-age, able-bodied adults are being imposed without adequate notice or clear standards, and they asked a federal judge to stop the plan from taking effect until these concerns are addressed.

The complaint was filed on behalf of two Philadelphia residents.

The system violates the Social Security Act and constitutional guarantees of due process, the lawsuit says.

In a statement Monday, the Corbett administration said that it disagrees with the lawsuit's contentions and that it would work to avoid confusion or disruption of service. People can be enrolled in a different plan if their medical needs demand it, the Department of Human Services said. Corbett leaves office Jan. 20.