Police say the missing diver off the Canterbury coastline is Seddon Ralph Jane, aged 42 of Wairoa.
The man went missing off Banks Peninsula, Canterbury.
The National Police Dive Squad will continue the search for him tomorrow morning.
Police said earlier that Jane was expected to surface at 9.45am but after failing to do so, authorities were alerted at around 10am.
The search is at a top Akaroa diving spot where until 3pm today, a helicopter and up to eight boats searched the area between Damon's Bay and Flea Bay.
"All we have at the moment is that police were notified this morning of a possible missing diver in the area of Damon's Bay and Flea Bay, near Banks Peninsula," a police spokeswoman said earlier in the day.
"There is a search involving the Coastguard and a rescue helicopter."