A judge is expected to release a decision on Monday as to whether to release a Korean man who has spent three years in Mount Eden prison without being charged.
Kyung-Yup Kim, who is a permanent New Zealand resident, is wanted in China in relation to the death of a woman in Shanghai in 2009.
China sought the extradition of Mr Kim in 2011 to face a charge of intentional homicide, but he has fought that request in a series of court actions.
His lawyer, Tony Ellis, challenged the legality of the man's continued incarceration in the High Court in Auckland during a two-hour session on Friday.
Dr Ellis said Justice Brewer had reserved his decision until Monday.