It has long been considered a rural myth but scientists are examining new evidence that a large cat - potentially a jaguar - is thriving in some parts of New South Wales.

There are now 220 sightings of a big cat in the western Sydney suburbs around the Hawkesbury.

Scientist Rob Close, from the University of Western Sydney, says paw marks indicate there is strong evidence it may be an exotic cat species.

"There are some big paw marks that have been identified that have been identified as panther identifications," he said.

A large number of domestic animals, including goats and dogs have been savaged in the area.

Resident Michael Williams says the kills are too big to be the work of a domestic dog or cat.

"We're dealing with an animal that's eating out 20 to 40 kilograms in a sitting," he said.

The State Government is examining the data.