Police said they began the pursuit after a vehicle was seen speeding in the city centre at about 11.13pm.
They said it is believed the car continued to drive at speed on Blenheim Road.
Police said they weren't in pursuit of the vehicle at this stage but laid spikes in an attempt to stop the vehicle.
The vehicle hit the spikes and crashed into a tree, catching fire, they said.
Police said all three occupants died at the scene. They were working to notify and support their next of kin and the staff involved.
So, just to be crystal clear, they decided to stop a vehicle using an inherently risky method, and people died as a result. And they almost certainly violated police policy in doing so. According to this 2016 IPCA report, road spikes are not to be used if "injury is likely to occur to the public, Police or the occupants of the fleeing car". Using them where there are trees to crash into means injury is likely to occur.
If you or I deliberately caused a fatal car accident in this manner, we would be charged and prosecuted. Isn't it time police officers who show a depraved indifference to lives of the public are subject to the same law as everybody else? Or are their egos, the blow to the confidence of arresting someone later when it is safe to do so rather than pursuing them like mad dogs, more important than human life?