A slip just metres from the main road between Haast and Fox Glacier poses no threat to motorists, New Zealand Transport Agency says.
Locals using State Highway 6 on the West Coast said a massive landslide below the road near Knights Point had worsened since it first occurred four years ago.
They worried that if it gave way any further it would take the road with it, sending motorists into the sea below and leaving the West Coast cut off from the south.
However, NZTA's regional performance manager Pete Connors said the slip had moved very little since 2012.
He said it was being monitored by sensors for movement and moisture levels, and visual inspections were being carried out each week.