Searches are poised to go into the Arthurs Pass region to look for an Israeli tourist who failed to turn up to a hut.
Police say the 22-year-old woman was with a party of four when they lost sight of her while tramping between Edwards and Hawdon Huts yesterday.
Her party waited for her before going to the next hut and alerting the Department of Conservation.
Search and rescue teams were being put on standby and a decision to go into the area would be made at 8am if she had not arrived at the hut.
A police spokesman said there were no real concerns for her safety as she was well-equipped to spend the night in the bush.
She had food, a tent, wet-weather gear and a torch.
"We don't know if it's a problem until daylight. Search and rescue will be mobilised at daylight but given her preparation and resources we're not too concerned at this stage," he said.
There is an alert on the Edwards-Hawdon route after heavy rain significantly damaged the track and structures.
The route is described as a three-day tramp over two alpine passes and spectacular rock-fall. Rivers are not bridged.
It is only recommended for people with a high level of remote-area experience, navigation and survival skills as complete self-sufficiency is required.