SYDNEY, Nov 27 (Reuters) - Britain's tabloid Daily Mail unveiled plans on Wednesday to launch an online site in Australia early next year, joining The Guardian and increasing pressure on local newspaper publishers Fairfax Media Ltd and News Ltd.

Daily Mail publisher Martin Clarke said he plans to hire 50 local journalists, with an editor to be appointed in the next few weeks.

The investment by The Guardian and The Daily Mail contrasts with belt-tightening by Australian publishers, which are struggling with a massive shift online and declining advertising revenues.

Fairfax, News Ltd, Rupert Murdoch-controlled News Corp's Australian unit, and smaller rival APN News & Media Ltd have all announced restructures and sweeping job cuts during the past year.

The Daily Mail's website MailOnline is the world's biggest English language newspaper website with 57.3 million monthly unique visitors globally, according to comScore.

Around one million of those are in Australia, making it "an obvious market," Clarke said.

"We are going very nakedly for a scale play," he told reporters.

The Daily Mail's Australian site, a joint venture with Nine Entertainment Co's digital arm Mi9, will be free to view, as is The Guardian.

Providing local content free will likely put pressure on Fairfax and News Ltd's paywall models, which are central to their earnings growth plans.

Clarke said he expected the venture to be profitable "pretty quickly."

The Guardian has built up to a reporting staff of 30, including a handful of high-profile political reporters, since launching six months ago.