Piha beach and lagoon Photo: RNZ/Anusha Bradley
Police were alerted about 5.20pm.
A search for the 37-year-old man began soon after, involving the police launch Deodar and Eagle helicopter, as well as Surf Lifesaving New Zealand members and Coastguard New Zealand.
A large area has been searched, but the man has yet to be located, police said in a statement.
The search has been suspended for the night.
Police say officers are providing support to the man's next of kin.
