A convicted murderer in Oregon is suing for the right to die by lethal injection after accusing the state governor of cowardice for announcing he would not authorise any more executions but granting only a temporary reprieve to death row prisoners.

Governor John Kitzhaber this week asked for the state supreme court to force Gary Haugen, 50, who has spent almost all his adult life in prison, to accept a stay of execution until the state legislature or a public referendum decides the future of capital punishment. But Haugen said that life on death row is soul destroying and mind numbing. He won a court order last month for his execution date, originally set for last December, to be reinstated in protest at what he calls a "broken system".

Haugen was condemned for murdering a fellow inmate nine years ago while serving a life term for beating his former girlfriend's mother to death with a hammer and a baseball bat in 1981.

Kitzhaber issued a moratorium on executions last year, saying he regards the death penalty as "morally wrong". Haugen initially welcomed the move because he thought it amounted to a commutation of his sentence to life imprisonment but turned against the governor when he realised he was receiving only a temporary reprieve while the future of Oregon's death penalty is decided.

If the state does not scrap capital punishment, the reprieve would not stop the next governor from ordering the execution of Haugen or any one of the 36 other people, including a woman, on death row.

Haugen's lawyers argued that a reprieve, unlike a pardon, must be agreed by the condemned man. In August, a court agreed, setting the clock ticking again on his execution.

Haugen said it was his right to choose to die.

"This is my free will. This is my constitutional right," he told the court. "You know, we need to put this to sleep. That's probably the wrong expression."

Kitzhaber, a former doctor who favours cowboy boots at the statehouse and wore jeans to his inauguration, announced the moratorium in November just two weeks before Haugen was to be put to death. He said his authorisation of the executions of two men during a previous term as governor in the 1990s had been "the most agonising and difficult decisions" he made in office and that he no longer believed in capital punishment.

"The death penalty as practiced in Oregon is neither fair nor just, and it is not swift or certain. It is not applied equally to all," Kitzhaber said in announcing the moratorium. "It is time for Oregon to consider a different approach. I refuse to be a part of this compromised and inequitable system any longer, and I will not allow further executions while I am governor."

Kitzhaber said a particular problem is that only condemned prisoners who abandon the lengthy appeals process out of desperation are ever executed.

"It is a perversion of justice that the single best indicator of who will and will not be executed has nothing to do with the circumstances of a crime or the findings of a jury. The only factor that determines whether someone sentenced to death in Oregon is actually executed is that they volunteer," he said.

Jeff Ellis, director of Oregonians for Alternatives to the Death Penalty, said that no one has been executed in the state in the past half a century who did not effectively ask to die.

"We haven't had an execution of an individual who's gone through the entire court process in over 50 years in Oregon. You get individuals who either suffer from mental illness or who get so beaten down by the conditions of enduring life on death row that every decade or so somebody gives up. Every decade or so we execute somebody who gave up along the way. That is hardly functioning system," he said.

But the governor did not commute the sentences of those on death row to life imprisonment, as he had the power to do. He said that was not his decision to make given that a referendum voted to reinstate capital punishment in 1984 and he wanted the moratorium to prod the state legislature into a "long overdue re-evaluation" of the issue.

Haugen said he agreed with the moratorium but criticised the governor for leaving death row prisoners to continue to deal with an appeals process Kitzhaber said is discredited.

"You're not going to execute people, but you're going to continue to allow people to litigate in a broken system?" he told the Statesman Journal in Oregon's capital, Salem.

Haugen called the governor's decision to grant him a temporary reprieve rather than commute his sentence "a coward's move" that left him in a "void". The condemned man mocked the governor, saying he did not have the guts to carry out the execution.

"I feel he's a paper cowboy," he said. "He couldn't pull the trigger."

At a court hearing in July, Haugen's lawyer, Harrison Latto, said the reprieve was a form of torture.

"It could be a day, could be seven years. During that indefinite period of time, they're saying: sit tight and we'll tell you at the end of that period whether you'll be executed or not," he said.

The governor's attorney, Tim Sylwester, said Haugen cannot refuse the reprieve unless it has strings attached.

"He has a death sentence he can't challenge," Sylwester said. "Right now, you're serving a life sentence, it's unconditional. So you can't refuse it."

The judge who cleared the way for Haugen to seek execution, Tim Alexander, said he set aside his personal views in doing so.

"I agree with many of the concerns expressed by the governor, and share his hope that the legislature will be receptive to modifying and improving Oregon laws regarding sentencing for aggravated murder," he said in his judgement.

"Many Oregon judges with experience presiding over death penalty cases would concur that the current law requires spending extraordinary sums of tax dollars that could be better used for other purposes to enforce a system that rarely, if ever, result in executions."

Kitzhaber's spokesman, Tim Raphael, said the governor expects to prevail on appeal.

"We're confident the governor has the authority to issue a reprieve, and we look forward to getting clarity from the supreme court," he said.

Ellis said that although he would like to see the total abolition of capital punishment in Oregon, he understood why Kitzhaber chose the interim measure of a temporary reprieve for Haugen rather than commuting the death sentences of all those facing possible execution.

"I think the governor was attempting to balance the power that he has as the chief executive in this state to grant clemency but also wanting to keep in mind the democratic will of the people," he said. "I see his actions as completely consistent with the appropriate role of a governor in a democratic society."

Oregon has had a turbulent relationship with the death penalty. It was outlawed in the state from 1914 to 1920, and again for 14 years from 1964. It was scrapped again in 1981 but reinstated three years later in a referendum.

Ellis said he thinks attitudes are again swinging away from capital punishment.

"I think Oregonians are ready to abolish it again. The death penalty debate has turned from a relatively simple debate – the choice of do you think it's moral or do you think it's immoral? – to a much more complex choice of whether this keeps us safe and, more importantly, are there better alternatives? We now know that the cost of the death penalty is extraordinary. In Oregon, we pay these extraordinary costs and the only people we execute are folks who give up their appeal," he said.

It costs about $20m a year for the state to fund the legal process, including the mandatory 10 stages of appeal, as well as maintain death row – a significant amount at a time when the state is forcing deep cuts to education and other public services.

But Kitzhaber's move met with strong criticism from some prosecutors in the state and the family of Haugen's first victim.

District attorney Bernice Barnett, who sent another inmate to death row for murder, criticised the governor for not having told voters when he ran for election that he planned to impose a moratorium. Josh Marquis, another district attorney, accused Kitzhaber of failing to carry out his duty to follow the law.

Ard Pratt, ex-husband of the woman Haugen beat to death, called the governor's granting of a reprieve "a miscarriage of justice".

Haugen's defence lawyers last year attempted to argue that he is mentally unfit to decide his own fate because he suffers from attention deficit disorder, foetal alcohol syndrome and mental problems.

During a hearing on his competence, Haugen made clear he wants to die.

"Do you understand what the effect of the death sentence will be?" he was asked.

"Well, one of them will be that we'll never have to have this conversation again," Haugen replied.