According to Gowthorpe, two helicopters responded - a police Eagle and a Westpac Rescue chopper - along with three ambulances, three police vehicles, the Auckland Council Muriwai Ranger, Muriwai Fire and Emergency Volunteers and the Muriwai Volunteer Lifeguard Service Search and Rescue Squad.
"A lot of agencies and volunteers were involved for this one incident, this limits their ability to help other people," he said.
"I just want people to not go out if they are in doubt."
Gowthorpe said six lifeguards responded immediately on hearing of the vessel overturning.
"The incident occurred two kilometres up the beach from the Muriwai Lifeguard tower, where the 4WD track meets the beach," he said.
"This incident sparked a major and rapid emergency services response.
"The individuals in the boat are very lucky to be alive - the swell is pretty sizeable," Gowthorpe said.
"They were the only boat out, and it would appear that not all of them were wearing lifejackets."
Police were notified of the incident and emergency services, including an Eagle helicopter, Fire and Emergency vehicles and St John ambulances responded.
All of the people on board have made it back to shore alive, a police spokeswoman said.
A St John spokesperson says one patient was taken to North Shore Hospital with moderate injuries and two were treated for minor injuries at the scene.