Rock and debris have fallen onto SH3 closing the road through the Manawatu Gorge.

The Manawatu Gorge is closed after about 200 cubic metres of rock and debris fell onto the road early on Friday.

NZTA national media manager Andy Knackstedt said the rockfall happened on SH3, 5km from Woodville, about 1.30am.

The road was closed on Friday morning and is not expected to re-open until at least 5pm.

A rockfall has closed SH3 in the Manawatu Gorge.

Knackstedt said geotechnical engineers were there checking the the hillside with an aerial drone.

He said the engineers needed to be sure the area above the slip was safe for work crews to clear the material away from the road.

"There is further unstable material which will also need to be removed. We are anticipating that the road will remain closed until 5pm," Knackstedt said.

A rockfall has closed SH3 in the Manawatu Gorge.

Motorists are advised to take an alternative route along the Saddle Rd or the Pahiatua track.

People are asked to use caution and allow extra time for their journey.