Weeks after the government declared the Blue Mountains big cat file closed, a Sydney father has spoken of a terrifying encounter with a panther-like creature outside his home.

Peter Russell told NSW Police he feared for his life after being stalked by a large, ''completely foreign'' feline predator at Riverstone, on the fringes of dense national park bushland.

It has been sighted at least 12 times in the Riverstone area over recent years. On Thursday, the member for Hawkesbury, Ray Williams, warned the government to ''rethink'' its position or face being ''accountable'' in the event of a tragedy.

Referring to a report, released in October, that dismissed the validity of about 500 eyewitness statements, Mr Williams said: ''I appreciate [Minister for Primary Industries] Katrina Hodgkinson might have more important issues to deal with but, in accepting those findings, she is ridiculing the many hundreds who have seen this creature.