Schools will not inform parents on the availability of ethics classes until they have decided scripture or special religious classes are not for their children.
The new system followed the announcement by Education Minister Adrian Piccoli earlier in the week.
Greens MP John Kaye was sceptical of the new system.
‘‘The government will now force schools to hide the existence of ethics classes,’’’ he said.
‘‘Nothing in the Education Act requires this level of discrimination against the ethics classes and their providers,’’ he said.
‘‘This is simply the O’Farrell government delivering on a deal with the Christian Democrats for their vote in the upper house.’’
An upper house inquiry earlier this year found ethic classes should be retained in public schools.