The NZ Transport Agency (NZTA) says a major slip about 15km south of Kaikoura last night could close State Highway 1 for days.
NZTA Canterbury State Highways Operations Manager Peter Connors says the slip is about 100 metres long and could contain as much as 20,000 cubic metres of rock, has occurred between two road tunnels on the highway.
Conditions were to dangerous to work on the slip last night however contractors are now working hard to clear the slip.
Mr Connors says a detour is available for light traffic on Route 70 - the inland Kaikoura route . However, heavy vehicles will have to use SH63 Wairau Valley and SH7 the Lewis Pass to get south to Christchurch and beyond.
Up to date information on this slip can be found at www.highwayinfo.govt.nz(external link) or by phoning 0800 44 44 49.