Ontario Premier Dalton McGuinty says the debate over whether the province should block access to pornography on public computers is an important one, but warns the responsibility ultimately lies with parents.

Gerry Martiniuk, a Progressive Conservative member of the legislature, has introduced a private member's bill that would force libraries and schools to install internet filtering software to block pornographic websites.

The Liberal leader wouldn't say whether he'd support such filters, and is not yet sure whether such standards are up to the province.

At the end of the day, McGuinty said, parents must keep on top of what their kids are doing, installing filters at home if necessary.

Gerry Martiniuk, an Opposition member who represents the riding of Cambridge, says it's unrealistic to expect library or school staff to constantly monitor the sites accessed by their computers, so filters are needed.

He says some schools and libraries already have such filters, but he wants them all to have them so the policy is uniform right across Ontario.