"It's much better for parents to take a strong interest in what their children are doing. Their degree of supervision needs to correspond with their maturity."

The group discussed the wider implications of Web filtering, beyond its technical ramifications, in a meeting last week in Google's Sydney offices.

has pointed to the trials in response to suggestions the technology is not up to the job, and says the scheme is part of wider plans to combat the proliferation of child porn, including education and law enforcement.

Hill said teachers and parents should investigate material on sites such as Wikipedia before allowing children access.

The false entry was removed within an hour by Wikipedia's internal content filtering technology.