Commonwealth Consolidated Acts Commonwealth Consolidated ActsWhere, on the day on which a registered maintenance liability first becomes enforceable under this Act or again becomes enforceable under this Act, a garnishment or attachment of earnings order made by a court under the Family Law Act 1975 , the Matrimonial Causes Act 1959 or the law of a State or Territory is in force in relation to the liability, the order ceases to have effect in so far as it relates to amounts payable under the liability in relation to the child support enforcement period.