Promphat and Child Support Registrar (Child support)

This matter concerned an appeal to the Administrative Appeals Tribunal concerning a decision by the Child Support Registrar regarding the percentage of care for a child. The appellant, Promphat, sought to challenge the Registrar's determination that there had been a change to the likely pattern of care, which led to the revocation of existing percentage of care determinations and the making of new ones.

The Tribunal was required to determine whether the Registrar’s decision to revoke the existing percentage of care determinations and make new ones was correct. A key legal issue was whether the repealed legislation, specifically the *Child Support (Registration and Collection) Act 1988* (Cth) as it stood prior to its amendment, should apply to the dates of revocation, or if the amended legislation should govern.

The Tribunal found that the repealed legislation was the applicable law for determining the dates of revocation. It reasoned that the amendments to the *Child Support (Registration and Collection) Act 1988* did not have retrospective effect in a manner that would alter the application of the law at the time the Registrar's decision was made. Consequently, the Tribunal concluded that the Registrar’s decision was affected by an error of law.

The Tribunal set aside the decision under review and substituted its own decision, finding that the existing percentage of care determinations should not have been revoked on the basis of the Registrar’s original reasoning.