The Independent Police Conduct Authority and Serious Crash Unit are investigating.
Today's fatal crash brings the road death toll since January 1 to 136, up from 131 at this time last year.
In the past 12 months 384 people have died on New Zealand roads, up from 341 in the previous year.
This morning's road death follows a chase in March when three people were killed after a driver fled police.
An innocent member of the public, Carmen Marie Yanko, died when the fleeing driver crossed the centre line and crashed head-on into her car near Nelson.
Two men in the fleeing car were also killed: 25-year-old Johnathan Tairakena and 33-year-old Phillip Jamie Stretch.
Police have been criticised for their pursuit policy, as the public debates the need for high-speed police pursuits and calling on police to review their policy to prevent more needless deaths.
The Automobile Association said in March it thought the Government should consider banning pursuits.
AA motoring affairs general manager Mike Noon said one in five police pursuits ended in crashes.
Banning pursuits was "something we should look at and see how it is working in other conditions", he said.