About twenty trampers may be unaware that a cliff face near them has closed the only access road at a popular gorge north of Wellington - and they may have to be helicoptered out.
Tony Martin of the Kapiti Coast District Council said the Otaki Gorge Road was closed because of large cracks in the hillside.
He said the council would consider using a helicopter to transport people out if necessary.
The council was encouraging people to stay away from the area.
Geologists are checking whether the whole hillside could be slipping.
The road will be shut through the Christmas holidays.