The man who died in hospital after being found unresponsive in police custody has been named as Taranaki Fuimaono.
Supt Karyn Malthus said on Tuesday the 43-year-old died in Auckland Hospital after his arrest on Saturday evening.
"Police have been providing support to his family."
Fuimaono had been treated at Auckland Hospital on Saturday for unrelated reasons and was discharged. On his release, he was arrested at the hospital at around 6pm and taken into police custody.
Shortly after midnight, he was found unresponsive - an ambulance was called and officers gave him first aid, which included CPR.
However he died in hospital a short time later.
A critical incident investigation is underway into the circumstances surrounding Fuimaono's death and the matter has also been reported to the Independent Police Conduct Authority.
The Coroner and Worksafe NZ have also been notified.