A condemned Arizona inmate has died nearly two hours after being administered with a lethal injection in what his defence lawyer described as a botched execution that should have taken 10 minutes.

Arizona Attorney General Tom Horne's office said Joseph Rudolph Wood, a double murderer, was pronounced dead at 3:49pm (22:49 GMT), one hour and 57 minutes after the execution started.

Governor Jan Brewer said afterwards that she was ordering a full review of the US state's execution process, saying she was concerned by how long it took for the administered drug protocol to kill Wood.

Wood had filed several appeals that were denied by the US Supreme Court, including one that said his rights under the First Amendment of the Constitution were violated when the state refused to reveal details such as the supplier of the drugs.

His lawyers had filed an emergency appeal with the court while the execution was under way, saying Wood was "gasping and snorting for more than an hour".

Word that Justice Anthony Kennedy denied the appeal came about a half hour after 55-year-old Wood's death.

Family members of the victims said they had no problems with the way the execution was carried out.

"This man conducted a horrific murder and you guys are going, 'Let's worry about the drugs'", said Richard Brown.

Wood looked at the family members as he delivered his final words, saying he was thankful for Jesus Christ as his saviour.

At one point, he smiled at them, which angered the family.

"I take comfort knowing today my pain stops, and I said a prayer that on this or any other day you may find peace in all of your hearts and may God forgive you all," Wood said.

Drugs administered wrongly

The case has highlighted scrutiny surrounding lethal injections after two controversial executions, including that of an Ohio inmate in January who snorted and gasped during the 26 minutes it took him to die.

In Oklahoma, an inmate died of a heart attack minutes after prison officials halted his execution because the drugs were not being administered properly.

Arizona uses the same drugs, the sedative midazolam and painkiller hydromorphone, that were used in the Ohio execution.

A different drug combination was used in the Oklahoma case.

States have refused to reveal details such as which pharmacies are supplying lethal injection drugs and who is administering them, because of concerns over harassment.

The Arizona Supreme Court also delayed the execution Wednesday morning to consider a last-minute appeal about whether Wood received inadequate legal representation at his sentencing.

About an hour later, the state's high court allowed the execution to proceed.

Wood was convicted in the 1989 shooting deaths of Debbie Dietz, 29, and her father Gene Dietz, 55, at a car repair shop in Tucson.

Wood and Dietz had a tumultuous relationship during which he repeatedly assaulted her.

Dietz tried to end their relationship and got an order of protection against Wood.

Source: Agencies