An unclaimed bike that has been parked near a tramping track for four days has sparked a search and rescue operation on Great Barrier Island.
Police are appealing to the public for any information as to who owns the bike after it was spotted there on Monday.
"Police have today begun a search and rescue operation as our concern that a person may have gotten into trouble is growing.
"We are really keen to urgently locate the bike owner to ensure they are safe and well."
Authorities have released a photo of the black and yellow bicycle leaning up against a large rock near the start of a local tramping track.
An aqua-blue helmet has been carefully placed on the seat.
"Our enquiries have led us to believe that the bike - which has been left at the beginning of Palmers Track and Aotea Rd - has been there since Monday, February 17," police said.
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The Department of Conversation is now also involved and staff have been visiting huts and speaking to trampers in the area to try and find the owner.
Anyone with information is urged to call Auckland Police on (09) 302 6640