The search for elderly Auckland woman Pat Wearn, last seen on Monday, is into its fifth day.
The 73-year-old, who has Alzheimer's disease, was last seen when she left her Torbay home for her regular walk.
Yesterday more than 90 people, including police, land search volunteers and Navy and Air Force personnel, searched nearby areas and made door-to-door inquiries.
Police say Mrs Wearn is physically fit and healthy and although she is likely to be dehydrated and disoriented by now she could still be alive.
The police national dive squad searched waterways and ponds in the area and searchers scoured bush in the Lonely Track Road, East Coast Road and Glenvar Road areas.
There will be an expanded search of bush areas today and door-to-door canvassing will continue.