Police have confirmed five people have died after a boat incident in the Kaipara Harbour.
It follows a report to emergency crews at 3.30pm on Saturday afternoon.
Three others have been rescued and have since been taken to hospital, while a search for three more people will continue.
It's believed 11 people were on board the boat, the Francie, which operates fishing charters.
A search team will continue to comb the shoreline until the early hours of the morning, while an aerial search will get underway at 7am, weather permitting.
Conditions are not suitable for the aerial search to continue overnight, due to a large sea swell.
Boaties and pilots have been asked to steer clear of the Kaipara Harbour area while the operation continues. Police say emergency services require a safe working space around South Head.
Inquiries are being made into what happened to the vessel, and how people ended up in the water.