Journalists at some of Australia's largest newspapers launched a rare five-day strike Friday, downing tools ahead of the Olympic opening ceremony due to a rancorous pay dispute.

The strike hit the Sydney Morning Herald, The Age and Australian Financial Review, in one of the most significant acts of industrial defiance to hit Australia's troubled news sector in years.

It is estimated hundreds of journalists employed under the umbrella of Nine Entertainment have deserted newsrooms in major cities Sydney, Melbourne, Brisbane and Perth.

Several sports writers sent to Paris for the Olympics will also strike, despite parent company Nine paying US$200 million as part of a package deal to secure broadcasting rights.

"The Australian public relies on these journalists to keep them informed, to hold power to account and to shine a light on corruption and wrongdoing, but they cannot do it without safe and secure jobs," said union representative Michelle Rae.

Reporters picketed outside The Age newsroom in Melbourne, waving placards and clad in matching white T-shirts reading: "Don't torch journalism".

While the dispute is tied to pay negotiations, tensions have heightened after management recently unveiled a plan to slash as many as 90 newspaper jobs across the company.

"It's totally unacceptable that the company is asking workers to make a choice between a modest pay rise and the possibility of more job cuts," said Rae, adding that staff were seeking a "modest pay rise" in line with inflation.

Like many newsrooms across the globe, falling print revenues and the rise of social media have fuelled repeated rounds of job cuts across Australia's media.