PARENTS will not be told of the availability of ethics classes in their school until after they have opted out of special religious education, or scripture, under changes to be adopted by the state government.

A government-initiated parliamentary inquiry into ethics classes advocated the approach in April, angering supporters who claimed it was designed to impede their take-up in schools.

The Education Minister, Adrian Piccoli, confirmed on Tuesday that ethics classes will be retained in NSW schools but said the government would introduce the new system. This means parents will be first offered a place in scripture classes and only told about ethics in a follow-up letter if they opt out.

The Greens MP John Kaye described the change as ''a massive road block'' to parents being informed of ethics classes.

''The government will now force schools to hide the existence of ethics classes,'' he said.