Maritime New Zealand's rescue co-ordination centre led the complicated rescue of a man and woman aged in their 50s.
Search mission co-ordinator Neville Blakemore said the pair activated the distress alerting function of their InReach device last night at 5.30pm after the rock slide.
Mr Blakemore said being able to activate their device may well have saved the injured climber’s life - he had an arm badly broken in two places, concussion and a badly gashed leg.
The other climber was relatively unharmed and had roped the injured climber on to the steep slope to prevent him from falling and suffering further injuries.
Yesterday evening, the co-ordination centre requested a Helicopter Line helicopter to fly from Aoraki/Mt Cook with a Department of Conservation alpine cliff rescue team on board.
They could not get to the scene of the rock slide at 1800 metres altitude on Mt D'Archiac (50km northeast of Aoraki/Mt Cook) because of heavy cloud.
Instead, they landed the rescue team at Godley Hut to wait overnight, watch the weather and keep in contact with the co-ordination centre.
The centre had helicopters with night-flying equipment on stand-by in Christchurch and Greymouth.
Low cloud prevented the Christchurch helicopter flying but at 3am today, during a break in the cloud in the mountains, the Greymouth Rescue Helicopter was able to fly to the scene and winch down the alpine cliff rescue team.
At 7.30am they flew the climbers, who were well-equipped for the terrain they were traversing, to Greymouth Hospital.
