Lawyers for California's prison inmates on Thursday demanded Gov. Arnold Schwarzenegger be held in contempt by a federal court for his "bald defiance" of an August order to slash more than 40,000 inmates from the state's clogged prison system.

In court papers, prisoner rights groups argued that the plan released by the governor last month to relieve prison overcrowding fell so far short he should be held in both civil and criminal contempt "for his apparent defiance" of the judges' orders.

Among other things, they asked a three-judge panel to appoint a special prosecutor to initiate contempt proceedings against the governor.

"Defendant Schwarzenegger, as the person who sets state prison policy and determines how defendants will respond to this court's orders, bears ultimate responsibility for defendants' contemptuous conduct," the inmates' lawyers wrote.

The latest legal salvo in the decades-long legal battle over state prison conditions ups the stakes for Schwarzenegger and his top prison brass, who've been struggling for months to figure a way to comply with the court order while at the same time dealing with a decimated budget and recalcitrant Legislature.

Schwarzenegger, through a spokesman, said his plan will comply with the court's orders in five years without creating "undue risk to public safety."

In addition, the governor indicated the state will appeal the three judges' "arbitrary" order to the U.S. Supreme Court.

The three-judge panel in August found that California's prisons are so overcrowded that they violate inmates' constitutional rights because of the inability of the prison system to provide adequate medical and mental health care.

The court ordered state officials to present a plan that would cut at least 40,000 inmates from the prison population over the next two years, about a quarter of the prisoner rolls.

But Schwarzenegger and state prisons chief Matthew Cate filed a plan with the court that calls for lowering the inmate population by about 20,000 inmates over the next three years.

The governor also asked the court for more time to coax concessions from the Legislature, which failed to approve a package of Schwarzenegger-backed reforms earlier this summer that could have slashed about 37,000 inmates from the state's prisons.

Lawyers for the inmates say the governor could have submitted his broader reforms to the court, but chose instead to present an inadequate alternative that amounts to "utter contempt" for the judges' orders.

In addition to seeking civil contempt against Schwarzenegger, which would press him to comply with the prison orders or potentially pay ongoing fines, the inmates' legal team insisted the judges also hit the governor with criminal contempt to "punish" him for defying court orders.

The judges have threatened civil contempt sanctions against the state in the past. Legal experts say criminal contempt against a governor would be an extraordinary step for the judges to take.

"That seems pretty unlikely in this situation," said Rory Little, a Hastings College of the Law professor.

Schwarzenegger last month called his submission to the court a "comprehensive public safety plan" that balances the need to lessen prison overcrowding with concerns about releasing dangerous criminals.

The plan largely mirrored the Legislature's recent plan to cut the prison population by about 16,000 inmates, with some additional provisions.

The plan also relies heavily on new prison construction to ease overcrowding, which inmates' lawyers say is on shaky ground and would take far too long to correct the current conditions.

The Legislature, meanwhile, appears unlikely to move quickly on further reforms sought in the governor's plan, in part because it is caught up in other high stakes issues, notably Schwarzenegger's push for a water deal.

Shannon Murphy, deputy chief of staff for Assembly Speaker Karen Bass, said the Legislature is "continuously working on the issue," but doesn't anticipate any action before next year.

Republican lawmakers also submitted a brief to the court Thursday opposing even the plan submitted by the governor to the court, saying the judges' order disregarded improvements to prison medical and mental health care and "jeopardizes public safety."