Three men have released footage of what they claim is a Tasmanian tiger – proof, they say, the animal is not extinct.

Greg Booth, his father George "Joe" Booth and Adrian "Richo" Richardson on Wednesday revealed video and stills of what they say is a Tasmanian tiger, or thylacine.

But Tasmanian wildlife biologist Nick Mooney said there was a "one in three" chance the grainy footage showed a thylacine.

Mr Mooney said while it was "the most interesting bit of video I've seen", the camera's wide-angle lens distorted the image and the animal was "a bit small" to be thylacine.