Two helicopters searching the Waimakariri Gorge in Canterbury after a reported mayday call have been stood down.
A spokesperson for the Rescue Coordination Centre Steve Randle said an aeroplane intercepted call on an aviation frequency at 11.20am on Thursday.
Spokesperson Steve Randle said the pilot described the quality of the call as scratchy.
The helicopters did not find anything during a search of the entire gorge and have been stood down until further notice.
Mr Randle said no aircraft have been reported missing.
Garden City Helicopters spokesperson Neil Scott said there is no distress beacon signal, which suggests either the mayday call was a false alarm or that the aircraft has a broken aerial.