The new 111 GPS system has proven its worth, helping rescuers find a group of trampers lost on the Tongariro Alpine Crossing.
The group of four became separated on Saturday night, out walking in the cold and snowy conditions.
Two ended up at the Oturere hut, and the other two - cold and wet - phoned police at about 8:40pm. A rescue helicopter was dispatched to their location, but unable to land because of the bad weather.
Eventually the two at the hut went looking for their friends, and found them around 2:30am. One of the group was so cold they couldn't walk, and had to be carried back to the hut by the others.
Search and rescue staff reached the hut at 2:45am and stayed with the group overnight.
A helicopter was sent out early Sunday morning to collect them.
The GPS system for 111 calls was introduced in May, police calling it "an absolute game-changer".
There were over 843,000 calls to 111 in 2015 and 2016, and services responded to more than 149,000 emergency events.
"This automatically provides the probable caller location of anyone calling 111," said Police Minister Paula Bennett.