Authorities on Tuesday renewed calls for people to stay away from a whale that has been spotted in southern Hong Kong waters.

In a Facebook post, the Agriculture, Fisheries and Conservation Department (AFCD) released a photo of the whale with an apparent wound on its back, and said its condition is "concerning".

"The department is working to locate the whale by sea and air and further assess its health, and discuss with experts for appropriate measures to help the whale," it said.

The AFCD urged people to maintain a distance of at least 100 metres and slow down their vessels if they encounter any whales.

In July, a whale spotted off Sai Kung died following cuts possibly caused by a boat propeller. That sparked calls for greater protection of marine animals.