An incredible shot of a hungry croc with his lunch near the mouth of the Daintree River has been captured from a mustering helicopter yesterday.

In its jaws, the crocodile has what appears to be a large turtle, as it swims about 500 metres off the coast.

Brian Bartlett was mustering cattle at Cape Kimberly that day and posted the footage online.

“Just trying to get message out, large croc around 4.5 metres was swimming just south of Daintree mouth and half a kilometre out to sea, roughly in line with Wonga Beach.

"Seen from mustering helicopter, had a large turtle in its mouth,” he wrote.

Mr Bartlett said he was posting to warn residents, particularly around Wonga Beach of the croc’s presence.