Dalby said participation in the trial is important despite that he considers it a "dumb idea". He said child porn will not be cut back with content filtering technology.

Optus spokesman Maha Krishnapillai said it will participate in the pilot to establish the effectiveness of the filters.

"We want customers to be very comfortable with using the Internet and we do not want to have clumsy technology in place," Krishnapillai said.

"Optus is committed to work with government. There are real challenges about how it will be done."

The scheme has angered communications technologists and privacy activists who have raised concerns over the effectiveness and accuracy of the technology and the power it hands to government to potentially censor Web sites containing information on euthanasia or political protest.