Sergeant Ian Martin said the pair appeared to have almost no overnight or survival gear with them and were not prepared for a night in the bush.
"Some other people who were at the campsite notified the police.
"They said they would be away for two hours for a hunt and they did not turn up.
"I don't think they had much experience and they did not have the equipment necessary."
Searchers from Queenstown and Dunedin would join the search today, he said.
On Sunday afternoon, police search and rescue personnel conducted a ground and aerial search using thermal and night vision technology from a helicopter.
The search would resume today with police search and rescue personnel, LandSAR, Amateur Radio Emergency Communications personnel and search dogs.
Last week a tramper was found dead in the national park after searches in the Devil's Armchair area near the northern end of the Milford Track.