"The search and rescue planners are working closely with local whānau and community members whose knowledge of the area and skills in bushcraft have been highly valuable to the overall search effort.
"These local searchers have been relentless in their own search activities to locate Jason."
Wilson said the search had involved a local helicopter, drones and river-capable inflatable boats.
"The terrain is steep with thick native bush, many bluffs and narrow watercourses. Searchers have described the terrain as being incredibly arduous."
Another search was planned for this weekend, marking two weeks since Butler had been missing.
"It is possible that Jason has left the bush at some stage over the period he has been missing, and police are encouraging anyone to report any potential sightings.
"Anyone who has information about Jason or his whereabouts should call 105, referencing file number 211027/1881."