Funding Catholic schools and not those of other faiths equates giving them a privilege others don't enjoy, Ontario government lawyers agreed Wednesday, but said it's still a constitutionally protected right.

A Toronto woman is asking Ontario's Superior Court to order the government to stop funding Catholic schools because as a taxpayer who doesn't share the church's beliefs, she says it infringes her freedom of religion.

But as the funding was guaranteed in 1867 in the constitution, it is not subject to charter challenges, court heard.

Judge David Corbett, questioning the government lawyers, noted that section of the constitution was put in place at the time of Confederation to protect the rights of the Catholic minority, when the Protestant majority had the benefit of a Protestant school system.

Today the school system is secular and yet Catholic schools remain publicly funded, turning a law that was once intended to protect minority rights into one that confers a privilege, Corbett said.

Josh Hunter, a lawyer with the Ministry of the Attorney General, agreed.

Ontario, he said, could create other denominational school rights, as other provinces have.

"We had an election on that a few years ago," he said.

In 2007, then-Progressive Conservative leader John Tory lost a provincial election after his proposal to extend funding to schools of other faiths became a controversial part of his campaign.

Reva Landau, the woman in this case, said Tory's proposal first gave her the idea to launch her challenge. She believes no religious school should be publicly funded, but said she thought at least Tory's idea was fairer than the current system.

"Someone who's Buddhist or Muslim or Jewish or atheist who wants to send a child to a school that promotes their particular philosophy has to pay for it fully out of their own pocket," Landau said outside court Wednesday.

"Only Roman Catholics get the chance to send their children to a school that promotes their philosophy without having to pay any extra out of their pocket. So if we live in a multicultural society does that seem fair? Does that seem just?"

The Roman Catholic school system gets about one-third of Ontario's $24-billion education budget, but only 23 per cent of electors direct their education taxes to separate schools.

The province asked the court to dismiss Landau's challenge because the case has already been decided, as the Supreme Court of Canada has heard four similar cases. The government suggested Landau isn't raising any new issues that would lead the Supreme Court to reconsider their decisions.

It should also be dismissed because Landau doesn't have standing, Hunter said. For a citizen to challenge a law there must be a link between them and the law.

"Otherwise any taxpayer could challenge any law they didn't like," he said. "You clearly have to have that direct link and paying taxes isn't enough."

The Canadian Civil Liberties Association is intervening in the challenge and is supporting Landau.

Landau is asking the Ontario Superior Court of Justice to order that the government stop funding Catholic high schools and only fund Catholic elementary schools to the extent they were funded in 1867 at the time of Confederation.

That would amount to being funded with "only property taxes from Catholics who declare themselves to be separate school supporters and who live within three miles of a separate school, and property taxes from wholly Catholic owned businesses," Landau wrote in her challenge.