On 14 July 2011, the Australian Energy Market Commission published the Tasmania Tranche 5a Procedure Changes Rule for the National Electricity Rules and its related final Rule determination.

The Commission's final Rule determination agrees to a transitional provision under Chapter 11 of the National Electricity Rules (NER) that enables AEMO to amend its Metrology, Market Settlement and Transfer Solution and B2B Procedures without complying with any process specified in the NER for the amendment of those procedures, including the Rules consultation procedures under rule 8.9.

The effect of this transitional provision is to facilitate the Tasmanian Government bringing forward the timing of its extension of retail contestability to customers in Tasmania consuming between 50 and 150 MWh per annum (Tranche 5a customers).

The Rule will commence operation on the 14 July 2011.