The earthquake that struck Christchurch on Tuesday has caused some 30 million tonnes of ice to break off from New Zealand’s biggest glacier.
Tour guides at the Tasman Glacier in the Southern Alps say the quake caused the ice to break from the glacier, forming icebergs.
Tourists say the icefall caused waves of up to 3.5 metres in height which swept up and down the lake for 30 minutes.
The glacier is about 200 kilometres from Christchurch on the west coast.
The powerful earthquake struck Christchurch around lunchtime, toppling tall buildings and churches, and crushing buses.
Prime minister John Key is warning the death toll of 65 is likely to rise.
Helicopters and cranes have already plucked terrified survivors from danger, but more than 100 are still missing after scores of buildings were reduced to rubble within seconds.
The spire of the city’s historic cathedral also crashed to the ground in the second major quake to hit Christchurch in five months.
Cold temperatures and rain is making it harder for the people gathered at evacuation centres.