Search and rescue teams are deployed in Te Urewera to look for a woman and four children.
Police were alerted just before 4pm yesterday afternoon when the five people were reported overdue from a walk.
The age of the children ranges from four to nine.
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 continue today.
Anyone with any sightings of the walking party are asked to contact Bay of Plenty Police on 07 348-0099.