The vehicle was towed from the water by a tractor last night and taken to a secure facility and officers from the Waitemata Police Serious Crash Unit would spend today examining the vehicle.
At this stage it's not known who was driving the vehicle when it crashed, police said.
Police said they had spoken to a small number of witnesses but would like to hear from anyone else who saw the brown and silver-coloured four wheel drive on the beach yesterday afternoon.
Road Policing Manager for the Waitemata Police, Inspector Trevor Beggs, said based on witness information police believed the car was travelling at speed along the water's edge.
"It's either struck an object or has hit sand. The vehicle has then flipped and rolled several times."
He said all four occupants were thrown from the vehicle."At this stage we have been able to determine that seatbelts were fitted to the car.
"The fact that the occupants have all been ejected from the vehicle would suggest that they may not have been wearing seatbelts, but this will be confirmed once the car has been examined."
Mr Beggs said last night's response was a challenging and upsetting situation for everyone involved. He thanked everyone who assisted at the scene.
"We are working with local Iwi to co-ordinate a site blessing and this should take place in the next few days.
"Above anything else, our thoughts today are with the families of these young men. They have just been given news that will no doubt impact many lives forever," he said.
"No-one who sets out with their friends on a Sunday afternoon expects that it will end in such a tragic loss of life."
An Auckland Westpac Rescue Helicopter spokeswoman said it appeared that the Pajero had been travelling "at high speed along the sand".
"Our crew worked extremely hard to save him, but unfortunately our attempts were unsuccessful due to the extent of his injuries," said intensive care flight paramedic Russell Clarke.
The wreckage of a four wheel drive vehicle is loaded onto a tow-truck on Muriwai beach. Photo / Daniel Hines
All four bodies were airlifted to the Muriwai Beach Surf Lifesaving Club at 6pm.
It is the second 4WD crash with multiple fatalities on Muriwai Beach. In July 2004, Soon Sung Yim and his wife Myeoung Heui Kim were killed in a crash alongside a visitor from Korea. Two other people were injured.
Rodney Area Commander Inspector Mark Fergus. said it was "logical" to assume the men knew each other but he did not know what their relationship was.
The Serious Crash Unit was investigating and Mr Fergus said it was too early to speculate on whether speed or alcohol were factors.
"Driving on the beach does carry with it certain risks. Speed is the greatest determinant," he said.
"It's important that people keep their speed down when they're driving on the beach. Of course conditions can change at any time."
A tow truck removes the badly-damaged vehicle. Photo / Greg Bowker
Police used a tractor to pull the mangled wreckage out of the surf and gloved officers and firefighters combed the tide line for evidence, collecting debris before it was washed away. "The scene is what it is," said Mr Fergus.
"We gather the evidence as swiftly as we can so that we're able to preserve it and answer some questions about what went on. So the next of kin can one day find out what's gone on."
The beach is considered part of the road network but users need a permit from Auckland Council to drive there.
Police, fire and ambulance raced against the fading light and tide to recover the bodies and crucial evidence. Photo / Greg Bowker
Vehicles on the beach must have safety equipment, stay off the dunes and slow down around people or animals.
The speed limit around the Coast Rd entrance is 30km/h. This rises to 60km/h north of Okiritoto Stream.
All the sand dunes, the New Zealand Defence Force Bombing Range and the Department of Conservation Papakanui Spit are strictly out of bounds.
Muriwai Motorcamp camp manager Steve Shearing said conditions for driving on the beach yesterday would have probably been idyllic.
"I went down about 3 o'clock for a look and the car park's pretty full."
The wreckage of the four wheel drive vehicle lying in the surf at Muriwai beach. Photo / OneNews
He said minor crashes were not unheard of but the vast majority of people who drove on the beach did so responsibly. "There's a large amount of people doing it."
New Zealand Four Wheel Drive Association president Tony Burgess said there were a lot of people driving on Muriwai beach - including parents with kids - with little experience.
"The normal road rules apply when you're driving on the beach, and it's not as easy as it looks.
"You shouldn't twist and turn or break hard and you shouldn't go into the water," he said. Mr Burgess said the organisation wanted people to be aware that there were hazards - such as buried cars, and other beach users - to think about. "We just want people to stick to the road rules really. And keep their seatbelts on."
Muriwai Surf Club callout squad co-ordinator Mark Goodhew said he had taken the police to the scene of the accident.
