TORONTO - Ontario could be the first province in Canada to create a website listing the names and addresses of its registered sex offenders -- a controversial proposal that's sparking a larger debate about whether it's an effective tool to stop crime.

Some experts say it would better protect children from predators, while others are concerned that it may lead to vigilante action or weaken a system that currently allows police to keep track of sex offenders.

If it comes to pass, the election promise by the Progressive Conservatives would go further than any other program in Canada that's designed to warn the public about high-risk offenders.

Alberta is currently the only province that has a website listing the names and photos of high-risk offenders. However, it doesn't provide their addresses for safety reasons.

If they form the next government, the Ontario Tories said they'll post the province's sex offender registry online, allowing public access to the names and locations of 14,100 individuals.

Jim Stephenson, who spearheaded efforts to create the provincial registry after his 11-year-old son Christopher was murdered by a convicted sex offender, opposes the idea.

"I don't think the public should have access to that information at all," he said in an interview.

Ontario has a very successful registry because the vast majority of sex offenders are complying with the law and providing accurate information about where they live, he said. And that's largely because they know the public won't have access to it.

"If that weren't the general thinking, sex offenders would simply not register and say, 'Forget it, I am not going to put my name on a register if the people in my hometown have access to that registry,"' he said.

Police would no longer have any idea where convicted sex offenders were living and "neuter" the registry, he said.

"Public access would be self-defeating to the general public and to law enforcement officers in general," Stephenson said.

Sex offenders can face charges if they don't comply, but provincial offences carry a two-year maximum and they'd likely only serve a year in jail, he noted.

"It's a small price to pay for your supposed freedom, so that no one would know where you are," he added.

Stephenson said he was surprised that the "poorly researched" idea is being floated by the Tories, who rejected it a decade ago when they were in power and created the registry.

It would put a "huge strain" on the administration of the registry, because some of Ontario's registered offenders are also on the national registry -- which isn't public. The conflict could also spark constitutional challenges in court.

"You would have a situation where if the province determined to make the information public, it would be counter to the federal legislation, where right now they're running side-by-side in tandem to provide authorities with the most up-to-date information on convicted and released offenders," he said.

But some experts believe it would do more good than harm. Paul Gillespie, a former Toronto police officer who co-founded the Kids' Internet Safety Alliance, said he supports the idea.

The website is "absolutely needed" to better protect kids from predators, said Gillespie, who headed the Toronto Police's well-known child exploitation unit.

"If people had any idea how many sex offenders were living in their neighbourhoods, they would be astonished, to be very honest with you," he said. "If they're considering buying a house or, in fact, somebody is on their street that might pose a threat, I think they deserve to know, so they can better protect their children."

But people should also ask themselves what might be the "unintended consequences" of making that information public, said Ann Cavoukian, the province's privacy commissioner.

Police already keep tabs on registered sex offenders and have the power to notify the public if there's a potential danger to a community, she said. Providing names and addresses could lead to a fear of retaliation or vigilante action.

"It could possibly lead to greater difficulty on their part, in terms of reintegrating into the community or genuine efforts at rehabilitation," Cavoukian said in an interview. "These are the concerns that come to mind, in my mind. Because if there isn't an enhancement of public safety, but there may be these negative consequences, then it might also lull the public into a false sense of security."

Tory Leader Tim Hudak defended his platform plank, saying people across Ontario are asking for the change.

"I respect there will be those who disagree with this approach," he said. "I just think it is the right thing to do. ... I believe that it's time that Ontario gave this information to parents to help them understand the risks to their young children in their neighbourhoods."

The Alberta website warns the public that the information should "under no circumstances" be used to "injure, harass, or commit a criminal act" against any of the listed individuals.

But there have been examples of vigilantism.

In 2006, a Nova Scotia man killed two American sex offenders before taking his own life after visiting an online registry that listed their names and addresses.

The 20-year-old dishwasher entered his name on the registry in order to get more information about the men, according to U.S. officials.

About 50 American states have similar websites, as well as federal authorities.

"I think it serves several symbolic purposes, but it's not proven that it affects public safety," said Martin Horn, a professor at John Jay College of Criminal Justice in New York and former commissioner of the city's Department of Corrections. "I think there's a logical argument to be made that it might, but I don't think that it's been demonstrated statistically that it does."