In a statement this afternoon, police said emergency services were called to the collision on State Highway 1 near the Ramarama off-ramp about 1.47pm today.
Counties Manukau Road Policing Manager, Inspector Tony Wakelin, said at this stage it appeared the vehicles have collided while travelling in northbound lanes, however the investigation will focus on exactly how that occurred.
“The three deceased were travelling in the same vehicle. This many fatalities at once is shocking and our thoughts go out to all those affected." he said.
“Incidents like this are hard on everyone involved and we are making sure there is support in place for those involved, their families, and our staff who have attended the scene.”
One victim in a critical condition and two others in serious condition have been transported to hospital, police said.
The Serious Crash Unit was at the scene.
Police want to hear from anyone who witnessed the crash or who might have dashcam footage.
Please get in touch on 105 or online via https://www.police.govt.nz/use-105 and reference job number P059766971.
Tamati Cassin, a motorist who arrived at the scene about 30 seconds after the crash, told RNZ he saw bodies as well as three other people with injuries.
As he approached the scene in his car, Cassin said he saw a "big dust cloud" across the motorway and the wire from a metal barrier was strewn across the lanes.
"There were several cars involved but the van was the worst and even the truck was pretty smashed up on the cab it's a tragic, tragic accident."
Cassin said everyone got out of their cars to try and help the injured and dead but it was "chaos" and no one was sure what to do.
"I just really feel for the driver of the truck and the people who have passed, I get to go home to my partner and kid but they won't get to."
St John said it sent 10 vehicles to the scene, including a helicopter, at 1.45pm and treated eight patients in varying conditions.
Six patients were transferred to "various destinations" including Auckland City Hospital and Middlemore Hospital.
Of the eight patients treated, St John said one was critical, three were moderate and four had minor injuries.
The New Zealand Transport Agency/Waka Kotahi said all lanes on SH1 between Bombay and Ramarama were closed.
Motorists heading south were being diverted at Ararimu Rd in Ramarama, while northbound motorists are being diverted at Mill Rd in Bombay.
NZTA Auckland systems manager Paul Geck told RNZ's Checkpoint programme the worst case scenario would be the road remaining closed until 5am on Tuesday.
Geck said the closure will "go into tonight" but he could not give an exact time.
- ODT Online and RNZ
