A ballot initiative approved by voters to speed up death penalty appeals was put on hold Tuesday by the California Supreme Court to consider a lawsuit challenging the measure.

The court issued a one-page decision staying the "implementation of all provisions of Proposition 66" and set a timeline for filing briefs that the court will consider before deciding to hold a hearing.

Proposition 66 would change how appeals are handled with the goal of expediting them so murderers are actually put to death. There hasn't been an execution in over a decade, and 750 inmates languish on Death Row.

The measure would appoint more lawyers to take cases, putting certain types of appeals before trial court judges and setting a five-year deadline for appeals to be heard. Currently, it can take longer than that for an attorney to be assigned to a case and upward of 25 years to exhaust appeals.

Former Attorney General John Van de Kamp and Ron Briggs, whose father wrote the ballot measure that expanded California's death penalty in 1978, filed the petition challenging the so-called reform measure. They said it would disrupt the courts, cost more money and limit the ability to mount proper appeals. The deadlines would set "an inordinately short timeline for the courts to review those complex cases" and result in attorneys cutting corners in their investigations, they said.

Supporters of capital punishment called the lawsuit a frivolous stall tactic.

Kent Scheidegger, legal director of the Criminal Justice Legal Foundation, said he didn't think the court's decision to hear the case was a reflection on the merits.

"It implies to me that they decided to hold off because there's no harm in holding off," Scheidegger said. "I think it has very little merit."

The challenge is based on four legal arguments, including that it violates the jurisdiction of courts by having Superior Court judges handle secondary appeals over issues such as newly discovered evidence, incompetent counsel or misconduct by jurors or prosecutors, said attorney Christina Von der Ahe Rayburn, who filed the case.

"The court has already recognized the seriousness of the issues at play by granting a stay," she said.

Death penalty opponents are also challenging time limits Proposition 66 sets for courts that could require them to put other cases aside to meet the deadlines. And they say it violates the requirement that ballot initiatives only cover a single subject.

The petition before the court said the measure incorporated unrelated elements such as provisions that allow condemned inmates to be housed at prisons other than San Quentin, where Death Row is located, and another that would turn over a majority of inmate income to their victims.

Von der Ahe Rayburn said the point of the single-subject rule is that voters shouldn't be confused by the combination of popular and unpopular pieces of legislation. The inmate restitution provision, for example, may have been popular with voters, but it is unrelated to the general goal of speeding up appeals.

California voters faced two death penalty measures on the November election. They rejected a measure that would have abolished the death penalty and narrowly approved Proposition 66. That initiative also included a provision that would funnel a large portion of inmates' meager income to victims.

This story has been updated.