Clifton helped Smith get a passport by making "an oral statement that he knew to be false" on June 26 last year.
Clifton had said he never expected Smith to leave the country. "If he didn't do this (escape) he would have got out," he said last month.
He was 18 when he met Smith in prison after he was sentenced to two years for assault with intent to commit robbery with a weapon.
He was addicted to drugs and said that while they were in prison together Smith helped clean him up. "He treated me nicely. I had a lot of people trying to beat me up and make me do certain things I didn't want to do - he protected me and looked out for me."
Clifton knew Smith was in for murder, but wasn't initially aware of the sexual convictions.
When he eventually found out about the sexual offending he said Smith played it down and told him he'd been about 17 and in a gay relationship with a 15-year-old boy. It was only after Smith's escape from New Zealand that Clifton found out the facts, he said.
He went to live with Smith's sister when he was released from prison, and would attend Smith's parole hearings and drive Smith's family members to the hearings.
Clifton also admitted further charges of possessing a knife and threatening to kill.
Those charges relate to an incident on December 20 when Clifton called police saying he was unable to cope with the pressure from media after his link to Smith was revealed.
His partner later called police after he had left the house dressed in camo gear and a balaclava, carrying a hunting knife.
He told his partner he "was going to die tonight".
Clifton was found with the knife and made threats to police. He is due to be sentenced on February 18.
