The Christchurch City Council has fenced off Sumner landmark Cave Rock, saying there is a danger of rock falls due to cracks caused by recent earthquakes.
Signs have been erected warning people not to climb the rock on Sumner Beach or enter the cave.
A council spokesperson says the signal station mast at the top of Cave Rock has also been damaged.
The spokesperson says recent geotehcnical reports indicate that the structure is not in danger of collapse and it is hoped to repair it in coming weeks.
The station signalled vessels approaching the Sumner bar when the wharf at Ferrymead was used to unload cargo for Christchurch in the 19th century.
