A mysterious “help” message written on the sand of isolated Lake Ahaura on the West Coast, spotted by a passing helicopter, has elicited concern from police.

Police are asking for any information about the message, wanting to hear from anyone who knows people who have ventured into the area recently.

Lake Ahaura is at least 58km from Greymouth and about 8km from the reclusive Gloriavale Christian Community in Haupiri, the nearest settlement.

The lake is surrounded by dense bush and mountains.

“We would also like to hear from anyone who may have written the message,” a spokesperson for police said.

“If you can help, please call 105 and quote event number P055875858,” she said.

Photographs of the message show other letters written in the sand but which are hard to discern.