New South Wales public school teachers have voted to fund legal action challenging the Government's constitutional right to fund private schools that use the money for religious purposes.
The New South Wales Teachers Federation has voted to fund the High Court challenge after the Industrial Relations Commission ruled that senior executives in Catholic schools should get a pay rise because of their role in building faith in the community.
The union is concerned that decision violates current legislation to stop Government funds being used for religious purposes.
Union president Maree O'Halloran admits the legal process could cost hundreds of thousands of dollars.
"We expect that it would be very expensive, but we have to do everything we can to ensure there's money in the public education system," she said.
Teachers were unsuccessful in similar action taken in the High Court more than 20 years ago.
The Catholic Education Commission says the legal challenge is a backwards step.
The commission's policy director, Ian Baker, says religious studies are taught for at least one period a week in all schools.
He says taking the issue back to court could wind the situation back by 50 years.
"We thought the issue was settled, settled legally in 1981, settled politically for the last quarter of a century," he said.
"So I'm not quite sure what's in the Teachers Federation's mind, but a return to the political debate of the 1950s and 60s, I don't think is on anyone's agenda."