The current New Zealand tax disputes resolution procedures were enacted in 1996 following a recommendation made by the Organisational Review Committee of the Inland Revenue Department in 1994. Yet, following their enactment and despite a number of positive aspects to the disputes resolution procedures, commentators and professional bodies alike have continued to raise concerns that inefficiencies, particularly with respect to time and cost, are affecting their operation and are, consequently, adversely impacting on taxpayers’ perceptions of the fairness of the procedures. It is believed that this is potentially negatively impacting on the tax system and on taxpayer voluntary compliance. Consequently, suggestions have been made for the use of alternative disputes resolution procedures, such as mediation, as another method to resolve tax disputes. The objective of this study is to develop a refined tax mediation regime for New Zealand through improving the features of the proposed tax mediation regime for New Zealand’s tax disputes resolution system first developed by Jone and Maples (2012b). Utilising a sequential mixed methods approach, consisting of a quantitative survey questionnaire followed by a qualitative focus group interview, this study seeks feedback on Jone and Maples’ (2012b) proposed New Zealand tax mediation regime from purposively selected practitioners (experts) in the tax disputes resolution and mediation fields. The feedback obtained is used in refining Jone and Maples’ (2012b) proposed tax mediation regime. This study finds that the most important aspect of the refined proposed regime is the inclusion of a mediator who is independent of both parties and moreover, that the mediator is foremost trained and qualified in mediation as opposed to being a specialist in tax law. The findings also indicate that mediation should not be made a mandatory phase of the disputes procedures. This study recommends that the refined tax mediation regime should be an administrative phase and incorporated with the existing conference phase in a proposed ‘ADR stage’ of the disputes procedures. Notwithstanding the potential budgetary and resource constraints, the findings indicate that if mediation were to be provided as a cost-free service, taxpayers (particularly small taxpayers) should be appreciative of the opportunity to put their cases forward and be heard, even if an agreement has not been reached through mediation. The literature suggests that this should in turn enhance taxpayers’ perceptions of fairness of the disputes procedures and thereby voluntary compliance. This study provides a foundation for the further development of tax mediation in New Zealand.