A Christchurch teenager will spend at least 15 and a half years in prison for killing a taxi driver.

Shannon Boyes-Warren, 17, last month admitted murdering Abdulrahman Ikhtiari in December 2008. The father of five, a refugee who brought his family to New Zealand from Afghanistan, was stabbed to death in his taxi in the central city.

Boyes-Warren's accomplice, Randell Brown, has been sentenced to five and a half years jail for manslaughter. He held Mr Ikhtiari from the backseat while Boyes-Warren attempted to rob him and inflicted the fatal stab wound.

Both received concurrent sentences for charges of assault with intent to rob.

In sentencing, Justice French told the court she had read the victim impact statements of Mr Ikhtiari's family and employer.

"These reports make for very sad reading indeed. The man killed in this cowardly and senseless attack was a man who had sought refuge in New Zealand in the hope that he and his family could live a safer life."