A helicopter has returned to the Mt Cook/Aoraki National Park in a bid to rescue two stranded climbers before dark.
An emergency beacon was set off by a man and woman shortly after 2pm at the top of the Copland track, 1800 metres high and about 10 kilometres west of Mt Cook.
The Rescue Coordination Centre initially deployed a helicopter to the area, but it was unable to land because of cloud cover.
It said a helicopter had returned to the site and was hoping the cloud cleared before 9pm.
The pair are experienced climbers and well-equipped.