Heavy rain in the past 24 hours and high river levels have worsened a landslide east of Greymouth, closing a section of SH7 until at least Tuesday.
State Highway 7 was reopened during the week to single lane traffic, but the slip has dropped by more than two metres, closing the road at Omoto between Greymouth and Stillwater.
Continuous heavy rain and high river levels have contributed to the 2.5 metre landslide, an NZ Transport Agency spokesperson said.
A short road detour is available just across the Grey River via Taylorville.
The highway will remain closed at Omoto until at least Tuesday morning given the recent movement, said Moira Whinham, maintenance contract manager for the Transport Agency on the West Coast.
The detour route is via Taylorville, with the turnoffs at Stillwater and Cobden bridges on the north side of the Grey River.