The New Zealand Transport Agency's West Coast senior asset manager, Mark Pinner, said contractors were remaining on site, about 15km west of the Gates of Haast, until dusk yesterday. They were continuing to clear the slip and remove as much of the rocks and debris as possible.
''A significant number of large boulders fell on to the road 1km west of Clarke's Bluff. These are extremely large and we are having to blast most of them to be able to remove them from the highway,'' he said.
''It is estimated 750 tonnes of rock has fallen. It will be blasted and removed to Burke Flat.''
A geotechnical expert was flown to the site early yesterday afternoon to check that the site had stabilised and that it was safe for motorists to travel through the area.
''Our contractors will be on site again at first light [today] to keep working on clearing the road. Motorists are advised to expect delays as this work progresses throughout the weekend,'' Mr Pinner said.
It was not known yet what had caused the massive rockfall. NZTA Christchurch media manager Jan McCarthy said she believed the rock material was of a similar type to that which fell in September last year at Izzy's Bluff, between Makarora and Hawea.
She estimated there was about 45km between that rockfall and the one yesterday.
