Internationally renowned big cat expert Dr Luke Hunter has dismissed claims that a mysterious large feline roams the Hills district, despite yet another sighting of the creature.

The latest sighting occurred in Berowra Valley at Hornsby Heights on Friday, July 18.

A Hornsby Heights resident, who asked to be known only as Kate, said her husband recently caught sight of a huge cat in bushland behind their property.

"It was on a Friday afternoon just after lunch and we were working in the garden," Kate said. "This animal moved very, very quickly and it leapt too.

"We could see the haunches. It seemed to be a greyish colour from the very quick siting we had and the surprise of it all."

Kate believes it could well be the same big cat that has been spotted by several people in the Hills district.

"I think it's probably the same cat as the one from the Dural-Kenthurst area and it has gone for a wander into Berowra Valley," she said. "I would like to see it again. It's just fascinating me."

Cryptozoologist Rex Gilroy believes this sighting could be connected to other big cat sightings as the animal has been known to follow the scrubland which goes all the way into the outskirts of the Hornsby area.

However Melbourne-born big cat conservationist and New York-based Panthera Foundation executive director Dr Hunter said the evidence available was not enough to support the theory.

Dr Hunter, who will be touring Australia as part of National Science Week also, said the usual evidence found with other species of mammals such as road kill, had not been found for these big cats.

"Every video-photo I've seen is too blurry to tell, or is very obviously a big domestic cat," Dr Hunter said.

"The other evidence produced dead livestock, paw impressions is either too poor in quality to say anything about them, or are quite clearly not the work of big cats."

To report any big cat sightings give Rex Gilroy a call on 1800 609 834.

Have you seen the mysterious Kenthurst Big Cat?

Email the Hills Shire Times at editor@hillsshiretimes.com.au

(Original headline: Expert queries big cat sightings )