Compliance with the Convention on the Rights of Persons with Disabilities (CRPD) requires substitute decision making being abolished and replaced with supported decision making. The current exploratory study involved a series of hui (meetings) with subject matter experts across the spectrum of the mental health care system to identify interventions facilitative of supported decision making; and the prioritisation of those in accordance with their own perspectives. A mixed-methods approach was used to categorise, describe and rank the data. Categories of intervention identified included proactive pre-event planning/post-event debriefing, enabling options and choices, information provision, facilitating conditions and support to make a decision, and education. The category of facilitating conditions and support to make a decision was prioritised by the majority of stakeholders; however, people from Māori, Pasifika, and LGBTQIA+ perspectives, who disproportionally experience inequities and discrimination, prioritised the categories of proactive post-event debriefing/pre-event planning and/or information provision. Similar attributes across categories of intervention detailed the importance of easily and variably accessible options and choices and how these could best be supported in terms of people, place, time, material resources, regular reviews and reflection. Implications of these findings, particularly in terms of the operationalisation of supported decision making in practice, are discussed.