A helicopter using a monsoon bucket was called in yesterday to drop water on the problematic Boundary Creek slip, above State Highway 6, 16km south of Makarora.
New Zealand Transport Agency Otago-Southland senior network manager John Jarvis said yesterday once loose material had been washed off the slip face, it was planned to use a digger to clear the tonnes of rock that blocked both lanes of the highway on Saturday night.
The road was closed yesterday but Mr Jarvis said provided more problems did not arise overnight - "always likely'' - at least one lane should be open later today.
State Highway 6 is the only direct link between Central Otago and Westland.
Mr Jarvis said the slip was "probably not quite as bad'' as the slip at the same place in 2012, which took several weeks and hundreds of thousands of dollars to clear.
