Car-sized rocks blocking the Haast Pass highway between Otago and Westland are
believed to have come down from Clarke Bluff in front of a bus.

Haast police constable Paul Gurneyt yesterday, said "apparently a 40 seater bus heading towards Haast saw it come down in front of them''.

He had no further details.

Constable Gurney said the rockfall followed five localised quakes felt within a few kilometres of Haast township.


"Very loud bangs, like an explosion, with a short sharp shock. All very shallow,'' Gurney said.

GNS recorded earthquakes around Haast including a magnitude 2.3 on Monday, a 3.6 last Wednesday and a 2.4 on August 5.

A 5.5 quake also struck the lower South Island on Monday night, after the rockfall
on Monday afternoon.

The highway is expected to remain closed until at least midday today.

New Zealand Transport Agency maintenance contract manager for the West Coast Moira Whinham said yesterday a geotechnical engineer on site had carried out a preliminary assessment of the rockfall and "agreed it is not straightforward to remedy today''.

It was expected it would take longer than originally thought for abseilers to remove loose material from the rock face.

The rockfall, blocking both lanes, was thought to have been triggered by recent rain and rain continued to slow progress yesterday.

Clarke Bluff is a narrow point on State Highway 6 just west of the Gates of Haast and has had rockfalls in the past.