A woman and four children are lost in the Te Urewera bush.
Police say they were called just before 4pm yesterday when the group were reported overdue from a walk in Te Urewera, in the central North Island.
The children are aged from 4-9.
They had been dropped off just after 1pm on Tuesday for a one- to two-hour walk.
Search-and-rescue teams and a helicopter have been searching in the Otamatuna Ridge area overnight and will continue today.