International human rights versus international obligations for extradition of suspected criminals. The Crown says Court of Appeal made mistakes in setting new legal tests for risk or torture and fair trial rights.

A controversial extradition decision involving an alleged murderer could head to the Supreme Court for a new hearing.

The 10-year saga took another twist in June when the Court of Appeal ruled Justice Minister Andrew Little must address serious questions about human rights in China - including the right to a fair trial and the risk of torture.

Kyung Yup Kim, who was born in Korea but moved to New Zealand when he was 14, is accused by Chinese officials of murdering Peiyun Chen while on holiday in Shanghai in 2009.

The 99-page judgment goes so far as to direct