Opposition Leader Barry O'Farrell announced last week that the Rouse Hill-based MP would be the Opposition's Parliamentary Secretary for Western Sydney.

Mr Williams will replace Baulkham Hills MP Wayne Merton in the job, as he will retire at the next election.

``As a tireless advocate for western Sydney I'm delighted that Ray Williams has agreed to take on this role,'' Mr O'Farrell said.

``Since his election to parliament, Ray's been a vocal advocate of the need to build the road and rail links required to improve transport services for people across western Sydney.

``He's proven to be effective in and out of parliament and in the media in taking the fight up to a state Labor government that's repeatedly failed to honour its promises to the people in western Sydney.

``Ray is an outstanding grass-roots MP with the knack of getting to the heart of issues important to the community.''

Mr Williams said it was a great honour.

``As a born-and-bred western Sydney kid from western Sydney parents it's a great opportunity to sell our message that we can offer the people of western Sydney a better alternative than the government we've got.''

Mr Williams will also be the chairman of the Liberal Party's Western Sydney Taskforce.