She said the driver was not trapped but firefighters helped police and ambulance staff to get him out of the wreckage.
The man was taken to Whanganui Hospital in a serious but stable condition. A hospital spokeswoman said this afternoon the man remained in hospital in a stable condition.
The incident is the latest in a string of crashes following police chases throughout New Zealand.
The police and Independent Police Conduct Authority are undertaking a joint review of police pursuits.
The review started in July and a report should be available to the public by late 2018.
A joint statement from New Zealand Police and the Independent Police Conduct Authority on November 10 said "drivers who choose to undertake high-risk driving behaviour when failing to stop for police, increase the risk to themselves and the public, including the risk of serious injury or fatality".
Police are involved in an average of 300 fleeing driver events (commonly referred to as "police pursuits") per month.
"While these events are challenging, dynamic and complex events, they only represent a small proportion (0.1 percent) of vehicle stops by police each year," the statement said.
The review is looking at all pursuits notified to the authority this calendar year, an estimated 75 pursuits. Most chases notified to the authority involve either death or serious injury.
It will also look at a random sample of 10 per cent of all other pursuits between July 1 and December 31 this year.
