Under the Guardianship and Administration Act 1993 (SA), the South Australian Civil and Administrative Tribunal SACAT is empowered to make guardianship and administration orders for a person who has a mental incapacity. Prior to 30 March 2015, this role was undertaken by the Guardianship Board.

Mental incapacity is defined as [s 3(1)] the inability of a person to look after her or his own health, safety or welfare or to manage her or his own affairs, as a result of:

Generally, an administrator deals with matters of finance, property and associated legal affairs, as distinct from a guardian, who may make decisions regarding personal and health care matters.

The principles of the Guardianship and Administration Act 1993 (SA) outlined in section 5 (see Principles of Substituted Judgement) require SACAT to consider the desirability of not making orders where a person's informal arrangements and networks are adequate and working in that person's best interests. Therefore, an application for a guardianship and/or administration order may only be required in the following circumstances:

Guardianship orders are often not required because most people are supported by family members and friends who make, or assist in making, decisions for the person concerned informally, that is, without any special authority. If a person has made an advance care directive appointing a substitute decision-maker it is unlikely that a guardianship order will be needed. The scope for informal financial management however, is more limited and the most important consideration is the protection of the person's finances from abuse or exploitation by others and/or poor self management. Consequently, administration orders are needed more often than guardianship orders.

Applications to SACAT for an order can be made by a number of people. The classes of people are [s 33(1)]:

Under the Act, a 'person responsible for the person' must have has a close and continuing relationship with the other person and be any of the following [s 3(1)]: