Two women continue to recover in hospital today after a head-on crash involving a convertible Audi on Auckland's Tamaki Drive last night.
At least one person was cut from the wreckage and police were investigating what roles alcohol and speed played in the crash.
Acting Sergeant Dylan Hannah-Jones said the injured were "very lucky'' to escape without life-threatening injuries.
Today two women, aged in their late 20s or early 30s, were in a stable condition in Auckland City Hospital, a spokeswoman said.
They had been rushed to the hospital in a serious condition with the two others who were later discharged.
Five people were injured in the smash and firefighters had to cut four from the wrecked cars.
Hannah-Jones said a silver Toyota Altezza was travelling towards the city when it crossed the centreline and smashed head on into a black convertible Audi.
"Alcohol and speed cannot be ruled out as factors but the investigation is continuing. Four people were injured, but none were life-threatening. They are very lucky; it is a spectacular mess," he said.
Olivia Hamlin was standing in the Tamaki Yacht Club carpark when she heard a car coming around the corner at speed.
"I could hear it speeding and changing gears down and as it came closer it missed the corner and just came over onto the other side of the road, narrowly missing one car and went straight into the front of the black car. It was a huge bang of windows smashing. The two cars just crumpled," she said.
"I was in shock. I just rang an ambulance and a girl hopped out of the passenger side of silver car with blood all down her face and coming from her eye," Hamlin said.
Police cordoned the scene as St John attended the injured as they were extracted from the cars by firefighters using the jaws of life.
A man, who only wanted to be named as Jim, said he was travelling behind the Audi.
"There were three people in the Audi - two women in the front and a man in the back - and two young women in the Toyota," he said.
He ran to the driver's side of the Toyota and held the girl's head and neck until emergency services arrived.
"She wasn't too bad. I thought she would be worse, put it that way. She seemed to have a broken femur and a very bad cut to the bone on her leg. She told me she had been drinking. She was in shock.
"It was amazing to see how the fire guys used all this equipment - saws and everything - to take off the top of the cars," he said.
Both lanes on Tamaki Drive were blocked and traffic diverted onto Ngapipi Rd from the city side of the accident and Atkin Ave at Mission Bay.