Another huge slip falls in Manawatu Gorge

Another large slip has fallen in the Manawatu Gorge which has been closed for three months due to previous rockfall.

About 10,000 cubic metres of dirt, rock and large boulders, slipped onto State Highway 3 following heavy rain over the weekend, the New Zealand Transport Agency (NZTA) says.

The new slip is at the Ashhurst end of the gorge, which hasn't been accessible since another 10,000 cubic metre slip came down in late-April.

NZTA Regional transport systems manager Ross I'Anson says the latest slip shows just how unstable the area is - and why it has been closed to vehicles for so long.

"This illustrates how prone the gorge currently is to slips due to the substantial movement recently measured in the hillside," he said in a statement.

The area is being checked over by engineers this afternoon.

Alternate routes are in place along Saddle Road and the Pahiatua Track.

Residents affected by the repeated closure of the gorge aired their frustrations at a public meeting last week.

The recent closure is the third major one in six years.

The NZTA is investigating long-term options to bypass or replace the gorge route, with a decision on a preferred route due in December.