The Constitutional and Policy Affairs Division advises government departments and bureaux on whether proposed legislation, or a particular policy, is consistent with the Basic Law, the provisions of international human rights treaties as applied to Hong Kong, and established principles underlying the legal system. It also has a specialist unit that addresses the need for advice on (and promotes understanding of) Mainland Law. In addition, the division plays an active part in law reform, through its responsibility for the relevant new legislation promoted by the Secretary for Justice.