Emergency services are responding to a serious crash on the Lewis Pass.

They received notification of the two-vehicle accident at 4.45PM.

It happened on the Shale Peak Stream Bridge, about 25 minutes in-land from the Hanmer Springs turn-off.

A police spokeswoman said initial reports suggest there are critical injuries.

The road will be closed for several hours while emergency services work at the scene.

Motorists are advised to avoid the area and follow diversions on Hanmer Springs Road and Springs Junction Road.

It’s understood one vehicle is upside down.

A rescue helicopter from Greymouth has been called to the scene.

NZTA said the road is closed between Springs Junction and SH7/7A Hanmer Springs turnoff.