Local boaties braved "messy seas" and "gusting winds" to save four people from a boat that was sinking so fast on the Manukau Bar the operators didn't have time to make a distress call.

Dramatic images show the boat barely afloat as rescue vessels approach at the Manukau Bar on Auckland's west coast.

Auckland Westpac Rescue Helicopter's chief intensive care paramedic Karl Taylor said the four boaties were spotted "clinging to the bow of the boat".

 

Papakura Rescue 1 crossed Manukau Bar at 1.14pm to join the search. Photo / Supplied

Coastguard spokesman Mike Buddle said it received the incident report via police at 12.44pm on Saturday, and Coastguard Radio immediately broadcasted a mayday relay to vessels in the area.

"Titirangi Rescue, Papakura Rescue 1 and Coastguard Air Patrol were urgently tasked. Local boats that had just crossed the bar, alerted by Coastguard relays, assisted with searching," Buddle said.

A Westpac Rescue chopper and Coastguard Air Patrol were also called to the scene.

According to a post on the Papakura Coastguard Facebook, the urgent callout was received for four people whose boat had capsized taking on water over the bow.

"The speed in which the boat started to sink meant that the boaties were unable to make a distress call on their radio and only one of them had his phone on him when they had to abandon the ship as it slipped under the water," it said.

"He was able to make a single urgent phone call to the police saying where they were before the phone was washed out of his hands by the swell."

With 33 knot winds and a falling tide, the seas were choppy and conditions at the bar was getting worse.

"Fortunately all four were wearing lifejackets and were able to stay close to their sinking vessel to make it easier for them to be seen," the post said.

Rescued boaties were transferred from local vessels to Coastguard. Photo / Supplied

"A fishing competition being held over the Manukau Bar greatly assisted the survival of the boaties as a number of vessels assisted Westpac helicopter and Coastguard Auckland Air Patrol in locating and pulling the boaties out of the water."

Buddle said two local vessels pulled two people each on board, and then moved to calmer waters to transfer the rescued boaties to Papakura Rescue 1.

"They were all cold but otherwise okay," he said.

Coastguards were on the scene within 30 minutes of being alerted, and received the "wet and shivering" boaties onto the rescue boat in "messy seas and gusting winds" where they were treated for mild hypothermia and shock.

The boaties were taken to shore where they were met by a waiting St John Ambulance and their families at Māngere Bridge.