Six newspapers in contested northwest Sydney suburbs are to fold as Fairfax Media declares them "no longer commercially sustainable".

Staff on the six Australian Community Media mastheads have been told that 11 jobs - seven in editorial and four in sales - will go through "voluntary redundancy" following the closure of the Hills News, Rouse Hill Courier, Penrith City Gazette, St Marys/Mt Druitt Star, Blacktown Sun and Parramatta Holroyd Sun.

A "proposed" new magazine publication is to replace them.

The papers are printed at Fairfax Media's nearby North Richmond print site, along with the Sydney Morning Herald, Australian Financial Review and other titles.

Rival News Corp Australia has eight mastheads in north and northwest Sydney under its NewsLocal brand, formerly Cumberland Newspapers.

Director of Fairfax's Australian Community Media John Angilley told staff the closures reflected the "limited long term sustainability" of the mastheads.

"A detailed assessment of the long-term viability of these mastheads shows they are no longer commercially sustainable for us to operate," he said.

Details of the title, content, format and distribution strategy of the new magazine were still being finalised.

The restructure leaves ACM with ten Sydney mastheads, the St George & Sutherland Shire Leader, Campbelltown Macarthur Advertiser, Camden-Narellan Advertiser, Wollondilly Advertiser, Blue Mountains Gazette, Hawkesbury Gazette, Hawkesbury Courier, Liverpool City Champion and Fairfield City Champion.

Pictured: The six doomed Fairfax papers and (above) NewsLocal's Penrith Press