UPDATED 4.02PM: A truck driver is in critical condition after a crash on Cambridge Road in the Waikato District.

Police attended a crash on Cambridge Road today at 1.45pm involving a truck which had rolled after colliding with a car.

This crash occurred between Parallel Road and Lamb Street, says a police spokesperson.

"The driver of the truck is in a critical condition in hospital.

"No one else has been injured. The road is closed and will be for at least another three hours.

"There will be diversions in place, so motorists are asked to follow these and delay their journey if possible."

The Police Serious Crash Unit and the Commercial Vehicle Safety Team are investigating.

EARLIER:

Cambridge Road in the Waikato District is closed after a truck rolled.

It happened just before 1:30pm between Parallel Road and Lamb Street, says a police spokesperson.

"The sole occupant of the truck is currently trapped - their injury status is not yet confirmed.

"There is a possible chemical leak from the truck, which is being dealt with by Fire and Emergency NZ."

Police are at cordons until the all clear is given from FENZ.