A federal appeals court that had blocked the scheduled February execution of a Georgia man whose lawyers say is mentally disabled has lifted its stay, clearing the way for a new execution date.

A three-judge panel of the 11th US circuit court of appeals said in an opinion published Monday that inmate Warren Lee Hill cannot submit his case to a federal court for reconsideration for procedural reasons, including the fact that his claim of mental disability was presented in an earlier petition and can't be presented again.

In the 2-1 ruling, the circuit judges also said Hill's claim only challenges his eligibility for the death sentence, not his underlying guilt, making him ineligible for reconsideration.

Hill was sentenced to die for the 1990 beating death of fellow inmate Joseph Handspike. Hill bludgeoned Handspike with a nail-studded board while his victim slept, authorities said. At the time, Hill was already serving a life sentence for the 1986 death of his girlfriend, Myra Wright, who was shot 11 times.

Brian Kammer, a lawyer for Hill, said he is pondering his next move following Monday's opinion.

"We are deeply disappointed," Kammer said of the decision, adding it would bar consideration of what he called compelling new evidence in Hill's case.

"The new evidence shows that every mental health expert ever to examine him finds that Mr Hill has mental retardation and he is thus ineligible for execution" under the US constitution, Kammer said in a statement.

The Georgia attorney general's office declined comment on the development.

The 11th circuit decision means a new execution date could be set at any time. But the state's supply of execution drug pentobarbital expired last month, and the drug has become increasingly difficult to obtain since its manufacturer has barred its use for executions.

The department of corrections will try to get more at the appropriate time, said spokeswoman Gwendolyn Hogan. No executions are currently scheduled in Georgia.

In 1988, Georgia became the first state to pass a law prohibiting the execution of mentally disabled death row inmates, and the US supreme court ruled in 2002 that the execution of mentally disabled offenders was unconstitutional.

But Georgia also has the strictest-in-the-nation standard for death-row inmates seeking to avoid execution. It requires them to prove their mental disability beyond a reasonable doubt. The state of Georgia has long argued that Hill's lawyers have failed to do that.

Since the supreme court ruling, many prosecutors have chosen not to pursue the death penalty if there's even a hint of evidence that mental disability is a possibility owing to the challenges that could be raised, said Richard Dieter, executive director of the Death Penalty Information Center.

What is unusual about Hill's case, he said, is that the experts who examined the inmate now seem to be in agreement that Hill is mentally disabled, but the courts are refusing to stop his execution based on legal technicalities, Dieter said.

The 11th circuit panel granted a stay in February after Hill's lawyers argued he was eligible for reconsideration in federal court because three doctors who had testified in 2000 that Hill was not mentally disabled provided statements in February saying they had changed their opinions and now believe he is.

In filings with the 11th circuit, the state said the doctors' new statements were not credible and also argued Hill was procedurally barred from asking a federal court to reconsider his case.

In the majority opinion, circuit judge Frank Hull writes that the court recognizes Hill has submitted new evidence to support his claims but says the core argument — that Hill is mentally disabled and therefore shouldn't be executed — remain the same. The 11th circuit and other courts have repeatedly held that new evidence and new legal arguments in support of a prior claim aren't enough to overcome the statutory bar on repeat petitions, Hull writes.

In the dissenting opinion, circuit judge Rosemary Barkett, writes that Hill has offered "uncontroverted evidence" of his mental disability and said she doesn't believe there is no choice but to allow the execution to go forward simply because his claim doesn't meet narrow procedural standards.