The crash was reported to police at 4.10pm and diversions have been put in place.
Traffic management was being put in place and motorists were asked to follow the directions of emergency services staff.
SH2 blocked by crash
The New Zealand Transport Agency said the eastbound lane of State Highway 2 between Monument and Dimmick Rds was blocked due to a crash.
“Please follow directions of emergency services in the area [and] consider delaying your journey or expect delays and possible diversions,” the transport agency said.
A police spokeswoman said it was a single-vehicle crash which had moderately injured one person and left two others with minor injuries. A tow truck had been called to remove the damaged car.