A man who murdered a Christchurch sex worker has failed in a last ditch appeal to New Zealand's high court

36-year-old Sainey Marong was found guilty of murdering Renee Duckmanton in 2018.

He was subject to a deportation order when he picked up Duckmanton from the city's red light district in May 2016, strangled her, and set her body on fire.

He was jailed for life with a minimum non-parole period of 18 years.

He claimed it was a miscarriage of justice -- but the Court of Appeal found the murder involved planning, with a high level of brutality, cruelty, depravity or callousness.

The Supreme Court has now found nothing wrong with that ruling.