Methven said the missing woman’s medical profile suggests she “may become unresponsive and curl up to a small position”.
The Pureora Forest is described as thick canopy with multiple waterways and waterfalls.
The missing woman is described as having a slim build and is 167cm tall, with grey hair.
She was last seen wearing trail type shoes, black pants, and possibly a silver jacket. She was also carrying a day pack.
Police advised hunters and landowners there would be a large number of LandSAR volunteers in the area across Easter weekend.
Volunteers from Hamilton, Waitomo, Waihi, Te Aroha/Paeroa, Taranaki, Tongariro, Thames, Tūrangi, Taupō, and Tairua/Pauanui/Whangamatā LandSAR are assisting.
“Safety is a high priority for both our volunteer searchers and hunters.
“Our searchers will be clearly identified with hi-vis orange Land Search and Rescue clothing and will be making noise such as whistle blasts and voice calls while searching,” Methven said.
Police have asked any trampers or hunters that were in the area on Sunday, March 24, to contact them on 105.
Any hunters that are planning to be around this area are advised to contact police on 111 if they see anything that may help to find the missing woman, and reference P058194666.
There are more than 15 Department of Conservation-managed walking tracks in the 78,000ha forest park, ranging from 10 minutes to three days in length.