TORONTO - It's not really up to the government to block access to pornography on computers at schools and libraries, Ontario's premier said Wednesday, amid a push for mandatory Internet filtering software to protect children across the province.

Premier Dalton McGuinty, who said he wasn't ready to commit to any new filters, said he believed that responsibility really should fall on parents themselves.

"You've got to take a personal interest in the technology in your home, you've got to understand what they've (your kids) got access to, there are certain kinds of filters that you can put in place," he said.

"It's really important for us not to devolve that responsibility to any authority or government."

Progressive Conservative Gerry Martiniuk, who represents the riding of Cambridge, argues it's unrealistic to expect library or school staff to constantly monitor the sites accessed by their computers.

Only between 25 to 35 per cent of schools and libraries have filters in place, Martiniuk said, because they aren't required to by law, and he wants an uniform policy right across Ontario.

"One of the misconceptions is that most libraries and schools are filtered," said Rob Nickel, a cyber safety expert and former OPP officer who supports the bill.

Last year, Nickel witnessed a man in his 60s downloading porn at the Cambridge Library, "viewing some of the most graphic material I've seen," as he sat beside two young children.

Library staff asked the man to leave, but told Nickel they didn't have filters to block such sites because of privacy and censorship concerns.

"We can't go to a corner store and see Playboys or Penthouse on the rack -- they have to be in wrappers, they have to be hidden from view, same with cigarettes," Nickel said.

"Yet our children can go into a public library and view any type of material they want, or somebody might be accessing material that they can happen by and see."

Education Minister Katheen Wynne insists that decision is up to the individual school boards, adding the schools are "very, very aware of this."

"There's some software that we worked on with the Ministry of Community Safety and Correctional Services that's gone into schools around the province," said Wynne.

"But they're going to be local initiatives."

The province has given $500,000 to an organization called KINSA, or Kids Internet Safety Alliance, which has worked in more than 3,000 schools to train adults and kids on Internet safety.

"We're very aware of this as an issue. One of my concerns is that it's not just at schools that kids are on computers so what's really important is that they're educated, that their parents and teachers are educated, in the broader issues of Internet safety, so they can know about how to use a computer safely wherever they are," she said.

NDP Leader Andrea Horwath called the debate an important one, but said she wasn't yet ready to say whether her party would support the bill.

"There's no doubt that there's concern about access young people might have to materials that are perhaps not something that their parents would let them have access to, so I think the debate and discussion is an important one, because we know that communications technology is forever changing."

Progressive Conservative Leader Tim Hudak said the bill hadn't been brought up in caucus yet, so his party had no official position.

Martiniuk said Netsweeper, a Guelph, Ont.-based company, helps provide safe access to school and library computers around the world and should be used across the province.

He also added he doesn't have any interest in Netsweeper, or in any filtering company, nationally or internationally.

Andrew Graydon, Netsweeper's chief operating officer, said it would only cost a small library a few hundred dollars over two to three years to install such software, adding it's not something his -- or any other filtering company -- would make much money on.

"I don't think it's a very big market if you're looking at the dollars," he said.