iiNet chief regulatory officer Stephen Dalby said the small error margins in the report will become gaping holes if the technology is deployed nationally.

"We think the solution is simply unworkable," Dalby said.

"Monitoring your children's activity and using a [local] content filter is far better than relying on some bureaucratic blacklist."

He said police who lecture with him at schools agree the best solution is parental supervision and user-level content filters and security measures.

Minister Conroy shut down the former government's NetAlert content filtering scheme last December, and redirected funds to the national filtering plan.

Speaking to Computerworld in a previous article on the content filtering scheme, director of an Albury-based ISP Ross Wheeler said the plan will hit the wallets of ISPs and consumers.

"I have no doubt, absolutely no doubt, that this will come straight out of the pockets of consumers and will sink small ISPs," Wheeler said.

He said Internet content filtering is impossible in Australia because of network configurations.

"If the government came to me and said you must filter this data, I couldn't do it."