In February, the company launched a three-year $170 million savings program to combat plunging circulation. Its share price is down more than 50 per cent from a year ago, amid 10 per cent a year falls in revenue.
Falls in newspaper circulation in March are believed to be the biggest on record, with the Sydney Morning Herald and The Age the worst offenders.
Fairfax's biggest shareholder and Australia's richest person Gina Rinehart has publicly criticised Fairfax chairman Roger Corbett twice in the last week over the company's performance.
Media Entertainment and Arts Alliance director of media Paul Murphy said the outsourcing decision was wrong, with sub-editors "the heart of the newsroom".
Regional newspapers were the strongest performers financially in print last year, but were being targeted, leaving Fairfax journalists confused, he said.
There have also been reports this week that News Ltd will announce between 400 and 1000 job cuts within days. The company axed about 12 jobs in Sydney and Gosford on Wednesday.
The MEAA's Mr Murphy does not think major cuts will happen at the moment, saying News Limited had been consulting openly with his union and had not said yet there would be redundancies.
However Australia's newspaper industry was given a dire outlook for the next three years by EL&C Baillieu Stockbroking media analyst Ivor Ries.
He said competitor websites such as realestate.com.au were posting record earnings, the take-up of devices like iPads was increasing and that meant more shrinkage for newspapers for another two-to-three years.
"The newspaper will be around but they will be smaller," he told AAP. "Within two-to-three years these papers will have more people working on the online product than on the print one."
Fairfax management has expressed disappointment at the decision of its journalists to go on strike.
The media company will continue to publish, says Fairfax Media chief Greg Hywood.
"Understandably our people are unsettled when they see significant changes to the way the business has operated in the past," he said in a statement on Wednesday.
"Fairfax Media is on a journey of change. We are reshaping the way we work. We must continue to do so to thrive in the future."
Mr Hywood said management remained committed to consulting with affected employees and their representatives about the proposed changes.
-AAP