More slips on Thursday night mean State Highway 3 through the Manawatu Gorge is likely to stay closed until next week.
The Transport Agency says more debris came down at a site that has kept the gorge closed most days since 18 August.
Regional highways manager David McGonigal says SH3 will be shut until the debris is cleared, a geological assessment completed and the agency is satisfied the hillside is stable.
He says the current closure is by far the longest since 2004.
Mr McGonigal says NZTA appreciates the disruption the closure is causing, but the safety of motorists is paramount.
Drivers are advised to use the Saddle Road or Pahiatua Track as an alternative route.