Everyone from the stricken vessel was now safe.
Coastguard NZ spokeswoman Monique Caddy said when the boat failed to report a successful bar crossing after 20 minutes the alarm was raised at the Coastguard operations centre.
There was no response from the vessel.
The Raglan Coastguard was sent and the Auckland-based air patrol was placed on standby.
"We called on all stations for assistance to see if they could find a vessel or anyone around that area."
Caddy said a vessel close to the bar saw a man in the water and pulled him out.
"The person plucked out of the water said two people had swum ashore, and directed the vessel to those people."
The remaining person was initially missing, but was quickly sighted and rescued after he was spotted on a distant rock.
All four on the stricken vessel were brought to Kawhia Harbour and checked by St John Ambulance.
Caddy said all four boaties were wearing lifejackets.
She said the dramatic rescue showed the need for boaties to take safety precautions.
"It just shows the absolute importance of logging a bar crossing and wearing lifejackets at heightened times of risk," she said.
"It certainly gave the best chance of a positive outcome in today's capsize."
Police said the incident was a reminder of how dangerous bar crossings could be.
"No matter how skilled you are in, or on, the water it's important to be prepared and aware of the conditions," Senior Sergeant Damion Rangitutia said.
"In this instance, those on board had taken several precautions. They were all wearing life jackets and had two forms of communication - a VHF radio and cell phones.
"They also logged their bar crossing with the Coastguard, which is great as it enabled a rapid emergency response."
The capsized vessel has not been recovered and may pose a marine hazard.
Anyone planning to take any vessel out in the Kawhia area is urged to be aware and contact the Harbourmaster or Coastguard to get the latest updates.
The incident is less than a week after seven men died when the charter fishing boat the Francie capsized trying to cross the Kaipara bar. Three men were rescued and one who is still missing is presumed to have drowned.