A court in the US state of Arkansas has been asked to halt what could be the nation's first double execution in more than 16 years because of fears their poor health could cause complications.

Lawyers for Jack Jones and Marcel Williams, both scheduled to be put to death by lethal injection on Monday, asked the Eighth Circuit Court of Appeals on Sunday to grant them stays of execution.

Jones' lawyers say he suffers from diabetes and is on insulin, has high blood pressure, neuropathy and had one leg amputated below the knee. He is on heavy doses of methadone and gabapentin.

They say he may be resistant to the lethal injection drug midazolam because of the drugs he is taking for his maladies and could suffer a "tortuous death".

Lawyers for Williams say he weighs 181kg and it will be difficult to find a vein for lethal injunction, so the drugs are unlikely to work as intended.

The state said the appeals are just delaying tactics and should be denied.

It was not clear when the appeals court will rule.

Arkansas originally wanted to execute eight inmates in 11 days by the end of April when its supply of midazolam expires.

It put to death Ledell Lee last week in the state's first execution since 2005. But four of the eight inmates have had their executions blocked by the courts.

Also on Sunday, two lower court federal judges ruled against inmates in separate cases.

Judge Kristine Baker denied a request from several inmates, including Jones and Williams, that the rules for witnesses to view the executions be changed.

Judge J Leon Holmes denied a stay of execution for Williams saying that the matter should be dealt with by the 8th Circuit Court of Appeals, because the inmate had already been appealed to the higher court.

Rush to execute

On Thursday, Arkansas put to death 51-year-old Ledell Lee, who had been sentenced to death for murder two decades ago.

In the run-up to his execution, there was a legal battle over the constitutionality of the lethal injection drug used to kill prisoners.

Arkansas has rushed to put to death three more people before its supply of the drugs expires at the end of the month.

Jones and Marcel Williams are scheduled to die on Monday and another inmate, Kenneth Williams, is set for execution Thursday.

READ MORE: Does a Texas man who killed no one deserve death row?

Both Jones and Williams have admitted they are guilty. Williams was sent to death row in 1994 for the rape and murder of Stacy Errickson.

Jones was given the death penalty for the 1995 rape and murder of Mary Phillips.

The US has put to death 1,448 people since 1976, according to the Washington, DC-based Death Penalty Information Center (DPIC).

Another 2,902 people are currently on death row.

Thirty-two states, as well as the US federal government, use lethal injection as their primary method for execution.

With recurrent legal efforts to effectively ban lethal injection, many states have alternative methods, including firing squads.