Six elderly Morrinsville trampers are missing tonight in rugged terrain west of Te Kuiti.
Police searchers on the ground were being assisted by a night-vision equipped helicopter.
Detective Bill Crowe, of the Waikato Police Search and Rescue Squad, said the missing trampers had been in cellphone contact with searchers. A member of the group raised the alarm in the afternoon by calling authorities by cell phone.
Mr Crowe said the group were well equipped and experienced. "The group of six people aged in their sixties and seventies are all experienced trampers and members of a Morrinsville club who had gone into the Whareorino Forest Park on Sunday," said Mr Crowe.
"They were due out [yesterday] however ... they used a cell phone to advise that they had lost the track and had been unable to find it again. The group thought they were on the Herangi Range however a helicopter sent up to locate [the group] and guide searchers to them was unable to find them."
Three ground teams made up of police staff and members of the Te Kuiti Land Search and Rescue Team were in the bush tonight.
"They will continue to try and locate the group, and with the onset of darkness we hope to be able to spot a fire the group are going to light by using the night vision equipment aboard a winch-equipped rescue helicopter brought in from Taupo.
"The group are fit, in good health and well equipped and have turned off all but one of their cell phones to save battery power to ensure they have a means to communicate with searchers and we hope to have them out of the bush and back with their families as soon as possible."