A 'Yowie expert' claims there are two different species of the mythical beast on the prowl in Western Australia.

Nick Slater says there are larger and smaller types in a new documentary called Amber in the Bush: Australia's Bigfoot Mystery.

'There's a couple of types of Yowies in Australia. We've got the big guys who are commonly referred to as a Yowie,' he said.

'There's also the little guys.'

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Yowie expert Nick Slater claims there are larger and smaller types in a new documentary called Amber in the Bush: Australia's Bigfoot Mystery (stock image)

Mr Slater said the average height of Yowies were reportedly sighted as six foot and ten inches.

Their defining features, he said, include an ape-like body covered in black and brown fur, as well as red or amber eyes.

'They don't want to be seen. If they are seen, it's for a reason,' Mr Slater said in the documentary.

The documentary also featured interviews with others who claimed to have sighted a Yowie.

Ryan Calgaret had gone hunting with family members at a blue gum plantation in Yabora, Perth one night, when he saw the silhouette of a 'great big huge man'.

He asked his brother-in-law to shine a torch where he was pointing his gun and the pair were shocked to see a hairy creature holding onto a tree branch.

'As the lights hit what I was looking at, this thing was just holding onto the trees with its arms,' he said.

Mr Slater said the average height of Yowies were reportedly sighted as six foot and ten inches (a Yowie reportedly spotted in Tamorine, Gold Coast)

A father claimed to have spotted the beast (pictured) earlier this week when hiking through the Burragorang area in New South Wales

Mr Calgaret said the alarmed Yowie then swung its arms from one tree top to another and he could hear the rustling of leaves.

There have been several reported sightings of Yowies across Australia.

A father claimed to have spotted one earlier this week when hiking through the Burragorang area in New South Wales.

Yowie expert Dean Harrison said Tamborine in the Gold Coast was a popular place for sighting the mysterious beasts, after claiming he saw one among the bushes.