Two people have been rescued from waist deep water after the car they were in plunged into the Waitematā Harbour and flipped.

The incident happened at mudflats off Pohutukawa Rd in Whenuapai about 10.55pm yesterday, a Fire and Emergency spokesman said.

Both of the vehicle's occupants were trapped when emergency services arrived but neither was badly hurt, the West Harbour Volunteer Fire Brigade said on its Facebook page.

Police officers helped one person out of the wreckage while fire fighters used hydraulic equipment to free the other person.

Photos on social media show the upside down vehicle resting in water at the bottom of a bank lined with dense foliage.

It was a "very close call", according to the West Harbour Volunteer Fire Brigade's Facebook post.

"The water was waist deep and with the vehicle upside down with no easy access. Thankfully no serious injuries."

Four fire crews - two from West Harbour and two from Kumeu - were at the scene last night.

The crash was one of four serious incidents on New Zealand roads overnight.

A teenager died after a police persuit involving a stolen car in  Wellington during the early hours of this morning.

A 15-year-old cyclist was killed in another collision - a hit and run - about 11pm on Auckland's North Shore.

Another person died after a crash in Ashburton that left three others with serious to moderate injuries.

That incident happened on Wakanui Rd about 3am.