A child has been killed and four others injured in a two-vehicle crash in Waikato this afternoon.

A four-wheel drive and a truck and trailer unit collided on Kakaramea Road (State Highway 39) at Ngahinapouri, near Hamilton, around 4.30pm.

The child was understood to have died at the scene and four people suffering minor to moderate injuries were transported to Waikato Hospital by ambulance.

It was understood three of the injured were from the same family as the dead child while the fourth person was the driver of the truck.

Police said an initial scene examination indicated the northbound truck and trailer unit had crossed the centre line into the path of the 4WD.

Serious Crash Unit staff were still carrying out their scene examination.

Kakaramea Road was expected to be closed for several hours while the examination was completed and salvage vehicles recovered the tractor and trailer unit.

Diversions for southbound traffic were in place at Finlayson Rd while northbound traffic was being diverted on to Ngahinapouri Rd.