UPDATED: A pre-schooler has been killed after multiple vehicles struck the child on a rural highway in the Hauraki Plains.

It's understood the young child lived at a dairy farm on State Highway 25 and ran out from a house onto the highway at 6.40am.

Police are investigating a fatal crash involving a child this morning.

It happened during dawn milking and it's understood the parents were at the farm.

At least three vehicles were travelling along the highway at the time. A local resident's son was on his way to work when the collision occurred, and was one of three cars in a line of traffic that were first on the scene.

"My son was one of the cars that hit [the child]. From what I understand they went out milking and somehow the child got out a door in the house, ran onto the road - it's shocking."

He understands the child was aged about three. His son was still at the scene being interviewed by police.

"As soon as he called, my wife went straight down the road."

A neighbour of the family was too upset to talk and visibly shaken by the incident. Other residents were waking to the news.

"Quite a few people at the school, even my daughter's teacher, were wondering why the kids were so late. They were still finding out."

The road was closed, diversions are in place and motorists are advised to avoid the area. Waitakaruru School has brought in a Ministry of Education trauma team to work with staff and students after the incident.

The principal did not wish to comment until the police had confirmed details.

Earlier:

A child has died following a crash on State Highway 25, in the Hauraki Plains this morning.

Emergency services were called to the scene at Waitakaruru at 6.40am on Thursday, says Waikato Police Senior Sergeant Robbie Hermann.

Robbie confirmed a child was involved in a collision with a vehicle, but says no other details are available at this moment.

Diversions are in place and expected to remain for at least the next hour.

The State Highway is closed from Canal East Road through to Pouarua Road, with a diversion route via Hopai West Road.

Northern Fire Communications shift manager Steve Smith says two fire crews from Ngatea were called to the "car versus pedestrian".

The call came from St John ambulance and one person had died, he says.

A section of SH25 is closed this morning. Image: NZTA.