Police hold "grave concerns" for missing tramper Alistair Levy in Kahurangi National Park.
Seven search teams, including a search and rescue dog, found no trace of him yesterday.
Search co-ordinator Sergeant Mike Fitzsimons said police held grave concerns for Mr Levy's welfare given the time that had elapsed since he was last heard from and the challenging terrain in the area.
He said intermittent rain and limited visibility was expected to clear late yesterday.
Levy reached the summit of Mt Owen on Sunday and had been expected to join wife Tracy and other family members in Christchurch on Monday.
The search started on Christmas Day in rugged country. Five teams, including a dog, cavers and the Nelson-Marlborough rescue helicopter, combed the area.
Police on Wednesday found a bicycle left by the 54-year-old Palmerston North teacher at the Kohatu cafe where he had arranged to leave it with the cafe owners.
Fitzsimons said a team of 13 cavers who have been in communication with police will be in the Bulmer area tomorrow.
A further aerial search is planned for today, after which options will be reassessed.
Police would like to speak to anyone who has been tramping around Mt Owen since Saturday.
Anyone with information is asked to call the Nelson police on 03 546 3840.
- The Press
Would you consider using your retirement savings to buy a home?Related story: Retirement savings used for first home