By Teresa Carson

PORTLAND, Oregon (Reuters) - A convicted killer spared lethal injection when Oregon Governor John Kitzhaber stopped all executions in the state last year is challenging that reprieve, saying he doesn't want to be a pawn in the governor's campaign to repeal the death penalty.

A lawyer for Gary Haugen, whose scheduled December 6 execution was halted by Kitzhaber's moratorium, told the governor in a letter released on Wednesday that he intends to ask for a new death warrant.

"While you have every right, of course, to lead a campaign to repeal the death penalty in Oregon, Mr. Haugen should not be forced to serve as a pawn in that effort," Haugen's attorney Harrison Latto said in the letter.

The letter stopped short of saying Haugen wanted to die but said that he no longer wanted live in legal limbo under an indefinite but impermanent reprieve, uncertain of whether or when he might be put to death.

Kitzhaber said in November he would allow no more executions in Oregon on his watch because he believed the death penalty was morally wrong, in a move that marked the latest salvo in the nation's long-running battle over capital punishment.

Sixteen states and the District of Columbia have no death penalty, and there has been a gradual trend away from capital punishment in the country, with the number of executions falling slightly in recent years.

But in announcing the moratorium, Kitzhaber stopped short of commuting the sentences of Oregon's 36 death row inmates to life in prison, saying the state's law on capital punishment was not his alone to decide.

Haugen, 49, whose imminent execution appeared to be the impetus for Kitzhaber's move, was convicted of killing his girlfriend's mother in 1981. He and another prisoner were both later convicted of murder for the 2003 killing of another inmate while Haugen was in prison for the first murder.

"Mr. Haugen does not feel that you are treating him mercifully by forcing him to remain in a kind of legal limbo that will last for an uncertain period of time ... at the end of which he might, or might not, be put to death," Latto said in the letter.

"Putting Mr. Haugen into that position against his will is more accurately described, in his view, as cruel and unusual punishment," Latto said, adding that he had filed papers in Marion County Circuit Court seeking to have Haugen's death warrant re-issued.

Latto said in the letter that Haugen rejected the "purported reprieve" offered him by the governor, and that Kitzhaber was not entitled to grant an indefinite reprieve.

A spokesman for Kitzhaber said on Wednesday that the governor was traveling and had not reviewed the letter.

"The governor's constitutional authority is clear," spokesman Tim Raphael said.

Kitzhaber, who was also governor from 1995 to 2003, has permitted the only two executions in the last 50 years in Oregon, one in 1996 and one in 1997.

"They were the most agonizing and difficult decisions I have made as governor," he said in his November announcement. "I do not believe those executions made us safer; and they certainly did not make us nobler as a society."

(Writing by Dan Whitcomb; Editing by Cynthia Johnston)