Nine's newspaper journalists will strike across the first weekend of the Paris Olympics if a deal can't be struck during crunch talks with management.
Editorial staff at the Sydney Morning Herald, The Age, The Australian Financial Review, Brisbane Times and WA Today will stop work for five days from Friday if the company doesn't bring an improved deal to the table.
The Media, Entertainment and Arts Alliance said more than 90 per cent of Nine's union members voted in favour of the strike.
The latest pay offer delivered a pay rise that did not keep pace with inflation and no agreement was reached on a diversity pay audit or quotas, the union said.
Workers were looking for a pay rise of at least 20 per cent over three years, but the company had only offered an increase of up to three per cent each year over that period.
"The company's pay offer fails to acknowledge cost-of-living pressures and management has not dealt with other claims from journalists including a genuine commitment to better workplace gender and cultural diversity, improvements to grade progression and protection through consultation in relation to AI," the union said in a statement on Monday.
"These mastheads are strong financial performers and have a reputation for award-winning journalism, and Nine needs to invest in its editorial front line ahead of its financial bottom line."
The pay dispute came against a backdrop of the company giving multimillion-dollar payouts to "misbehaving" senior executives and job cuts, the union said.
A Nine spokeswoman said management planned to meet with union representatives on Wednesday, when the company would "continue to negotiate in good faith with the bargaining committee".
Nine announced in June it would make 200 positions redundant across its broadcast, print and digital divisions.
The announcement followed downbeat half-yearly financial figures released in February showing a big drop in company-wide earnings, including from its publishing division.
Earlier in June, former federal treasurer Peter Costello resigned as Nine's chair after being accused of a physical altercation with a News Corp journalist at Canberra Airport.
Video of the incident appeared to show him knocking over the journalist after being confronted with questions about alleged sexual harassment by senior staff at Nine.
Mr Costello denied assaulting the journalist, saying the reporter fell after backing into an advertising placard.
Nine paid a reported $305 million for the broadcast rights to the next five Olympics Games, beginning with Paris.
