Waikato police say they are investigating whether two cars were racing each other just minutes before a Nissan Skyline crashed, killing its four occupants.
At a press conference at Hamilton Central Police Station this afternoon, Waikato road policing manager Inspector Freda Grace says "there are indicators that speed is definitely a factor in the crash".
"But what that speed is, at this stage, we are unable to determine but that is part of our ongoing inquiries."
A northbournd Nissan Skyline collided with a southbound van on Ohaupo Rd, at the intersection of Ingram Rd outside Hamilton Airport, about 10pm yesterday.
Police confirmed three men and one woman died in last night's accident. The men were 20, 19 and 28 years old and the woman was 24 years old.
When questioned whether the Nissan Skyline and another car were involved in "illegal street racing" on State Highway 3 between Te Awamutu and the crash scene Mrs Grace says it is too early to confirm anything but it will form part of their investigation.
"Like you we have witnesses who say that there potentially was another vehicle involved and we are continuing with our inquiries to establish exactly what part to play that vehicle had in it. We are appealing to anyone who saw a white Nissan and any other car that was with it driving between Te Awamutu and Ohaupo village between 9.30pm and 10pm last night."
The driver of the van remains in Waikato Hospital with a number of serious injuries to his legs.
Mrs Grace also confirmed there was an earlier incident at a petrol station in Te Awamutu involving the driver of the Nissan Skyline and a vehicle which was first to the scene of the crash. However, police were currently investigating what happened and wouldn't elaborate."
"We do understand that one of the vehicles was at the petrol station, yes and that somebody else that turned up to the scene had seen that car at the petrol station as well."
She says there is "illegal street racing" which occurs on Waikato streets but police were working with those involved.
"There is illegal street racing activity. I don't know if you can describe it as drag racing, but we are working with that group.
"We're very concerned about speed and are working with NZ Transport Authority and regional council about speed management for the Waikato district. It is something that's really important. It's just a matter of physics that the faster you go the bigger the mess."
Mrs Grace says the next of kin involved in the crash were still being notified about the crash and police would release names once that process has been completed.
"This is an absolute tragedy and an avoidable tragedy."
Mrs Grace extended her condolences to the families affected by the crash.
Earlier, eyewitness to last night's dramatic smash on Ohaupo Rd has told the Herald the impact split a car in two.
Panelbeater Steve Hartland, who lives on the corner of Ohaupo and Ingram Roads, said he could hear cars speeding towards his house before the sickening sound of impact.
"I could actually hear them going nuts coming down the road - that's what got my attention so I went up to have a look. The Skyline was on the wrong side of the road and he slid sideways and collected the van."
Mr Hartland said the impact of the crash ripped the Skyline in half. The back half was wedged into the airport's security fence and the other half was left on the road.
He heard a car with a loud exhaust leave the scene before he reached the roadside carnage.
"There was another car involved," he said.
Other motorists who had been overtaken by the speeding cars told him they had been passed by a Subaru and a Skyline drag racing each other on the open highway between Te Awamutu and Hamilton.
"Some of the people that were driving from Te Awamutu thought the accident was going to happen earlier down the road.
"The guy in the ute told me that as he was coming down the hill the Subaru was passing him and the Skyline was again passing the Subaru blocking all the lanes."
Mike Aldridge posted on Facebook a dramatic account of the moments following the collision.
"Saw this last night only a couple of minutes after it had happened.
"There was nothing left of the Skyline. Just a cloud of dust hanging gently in the air and an eerie silence."
He described how one man "in a bit of a daze" was walking along the growing queue of traffic telling drivers there'd been an accident.
"Such a tragedy for the families and friends involved," he wrote.
Mr Aldridge, who was heading towards Te Awamutu, said a nurse happened to be in a car that was one of the first to arrive at the accident scene and tended to the victims until emergency services arrived.
He did not notice any vehicles travelling at high speed on the state highway headed towards Hamilton in the minutes before coming upon the crash.
Motorists travelling on SH 3 just before 10pm who saw the cars were asked to contact Senior Constable Mark Strongman on 07 872 0100.