Fatal Kaiaua kayaking trip: Trio were wearing lifejackets when it flipped

The Waikato family had travelled to Kaiaua to go fishing, police say, also confirming they had all been wearing lifejackets. Photo / File

An 8-year-old boy was on a fishing trip with his father and sister when the kayak they were on suddenly capsized.

Acting Detective Senior Sergeant Michele Gillespie, Counties Manukau South Police, today confirmed all three had been wearing lifejackets but it wasn't enough to save the boy who later died in Starship Hospital.

Emergency services were called to Kaiaua about 3.30pm on Sunday after reports of the kayak capsizing.

Two Coastguard boats, a Cessna and two rescue helicopters were sent to the scene and all three were pulled from the water.

Crews were seen frantically performing CPR on the boy on the grass at the Kaiaua Boat Ramp before he and his sister were separately flown to hospital.

Gillespie today confirm the trio had travelled from the Waikato to go fishing.

Police were still investigating what caused the boat to initially tip over, but said initially the three were able to get back on it.

The father has been able to call for help using his mobile phone before the boat started taking on more water.

"It had started to take on too much water and this has caused further capsizes and the kayak to eventually sink."

The trio were in the water for some time before help arrived and transported them for emergency medical treatment.

"Police are still conducting interviews with witnesses in an attempt to establish why the kayak capsized in the first instance."

The investigation into how it tipped would include an examination of the kayak and a possible reconstruction of events that would be conducted in conjunction with Maritime New Zealand.

Gillespie said the boy's death had been referred to the coroner.