Warning signs have been put up at Changi Beach Park after a reported sighting of a crocodile in the area.

The Straits Times understands that the signs have been up since Monday.

Mr Yusaini Abdul Rahim, an Immigration and Checkpoints Authority officer working at Changi Ferry Point Terminal, first saw the crocodile on Monday morning while out on patrol. The 41-year-old then contacted the National Parks Board (NParks) and Agri-Food and Veterinary Authority (AVA).

He spotted the reptile again on Wednesday and posted several photos and videos of it on Facebook. The post has since received over 7,000 shares.

"My immediate priority was to warn the public to stay away as it can be quite dangerous," Mr Yusaini told ST yesterday.

He suggested that the crocodile could be the same one that was spotted at Pasir Ris Park earlier this month.

Sightings of crocodiles, while not uncommon in places such as Sungei Buloh Wetland Reserve in north-western Singapore, are much rarer in the north-eastern region.

NParks' group director of parks Chia Seng Jiang told ST that the board is aware of recent sightings of a crocodile in the waters around Changi Beach Park.

"On Aug 21, 2017, a crocodile was sighted in the waters off the beach area of the park," he said. "It was likely an estuarine crocodile (Crocodylus porosus)."

Estuarine crocodiles are known to swim freely in the Strait of Johor. They feed and rest in mangroves and freshwater bodies, and are usually found in the water or at mudflats away from visitor routes.

Mr Chia said NParks is working with the AVA and Animal Concerns Research and Education Society (Acres) to monitor the sightings of the crocodile, as well as to catch and move it to another location, for the safety of park users.

"NParks and AVA have also advised vessel owners, fish farmers, and operators of establishments along the coast to take the necessary precautions," he said.

Warning signs and advisory notices have been put up in the park near water edges.

"Visitors should heed these signs, in particular to keep to designated paths and away from water edges," said Mr Chia.

He also advised people who come across a crocodile to stay calm and back away slowly. They should not approach, provoke or feed the animal, and can call the NParks helpline on 1800-471-7300 for assistance.