TORONTO — Web surfers trolling for child pornography could soon find it harder to commit their crimes after an agreement among Canada's biggest Internet service providers to block hundreds of offending websites.

Project Cleanfeed Canada, based on a similar campaign in the United Kingdom, stops child pornography websites from loading, making it seem as if they don't exist.

Only the big ISPs have signed on so far -- Bell, Bell Aliant, MTS Allstream, Rogers, Shaw, SaskTel, Telus, and Videotron -- and are only blocking between 500 and 800 websites, but it's an excellent start for a project that will surely grow, said RCMP Supt. Earla-Kim McColl.

"Those that are looking for these types of sites will not be able to access them once they've been reported,'' she said, adding that the service will also prevent web surfers from unintentionally loading child pornography.

"People in Canada that accidentally come across child pornography websites, they report them, and then others won't have that same experience.''

The system could go online for some ISPs within weeks and may take as long as three months for others, said Lianna McDonald, executive director of Cybertip.ca, the national child sexual exploitation tipline that spearheaded the program.

The hundreds of other smaller ISPs across the country will also be urged to participate, she said, and new websites will be added to the offenders' list as they're found.

Unfortunately, the project won't entirely solve the problem, McColl said, because some expert computer users will still find ways to get around the system, and the number of child pornography websites is estimated to be in the hundreds of thousands -- or even millions.

"There are some sophisticated users that will be able to circumvent the system,'' she said.

"But I think for the person that is curious about this and doesn't realize the fact it's an offence and illegal material, it will stop those types of people.''

Users who attempt to access the sites also won't have their information tracked, she said.

"That's not (the ISPs') responsibility, to monitor who's doing what. This is just a question of these sites being illegal, and so we're just going to prevent people from accessing them.''

The federal government has lent its support to the program and applauded all involved.

"I'm very pleased to see the co-operation between the Canadian Internet service providers, Cybertip.ca and law enforcement in the ongoing battle to eradicate the online sexual exploitation of children,'' Justice Minister Vic Toews said in a release.

"Canada's new government welcomes this latest contribution to protecting children and making the Internet safer for all Canadians.''