A remotely-operated wildlife camera trap set up on the island by the City of Greater Bendigo to monitor birdlife snapped the mystery reptile leaving the water on Tuesday afternoon.

An image of the crocodile was leaked to the Bendigo Advertiser but the newspaper was later prevented from filming the reptile by a city employee keen to keep a lid on public concern.

The Addy showed the image to Northern Territory crocodile hunter Rodney Ansell who estimated the croc's weight at over a tonne.

"It's the biggest fresh water croc I've ever seen," he said.

Mr Ansell said fresh water crocodiles usually ate fish and small animals but warned residents to stay clear of the Weeroona island.

"People really need to be aware of the danger in approaching an animal of this size," he said.

"If you are forced into a confrontation the best strategy is to either climb a tree or punch it on the nose. Never look it in the eye - they hate that."

Mr Ansell said it was extremely rare for a crocodile to make its way so far south but such sightings were most common in early April.

The Bendigo Advertiser believes the crocodile will be visible on the island on Wednesday if readers wanted to go for a look.

More to come.

Source: Bendigo Advertiser