The Act changes legal status and therefore affects a range of groups and decision-makers in identifiable ways, as established by its provisions.
Individuals aged 18 to 20. The primary class affected is persons who are 18 years or older but under 21 at or after the commencing day. Section 5(1)(a) and (b) give these persons "full age and full capacity" either on attaining 18 on or after the commencing day or, where already aged 18 to under 21 on the commencing day, on that day. For these persons the label "infant" or "minor" in many contexts will cease to apply where the other enactment does not indicate a contrary intention (s 5(2)).
Legal counterparties and commercial actors. Persons and entities that contract with people in the 18-20 age bracket are affected. Where contracts, consents, guarantees or estates formerly required parental consent or guardian involvement because a party was under 21, those requirements will cease to apply for those dealings that fall within the Act’s scope (s 5(2)). Conversely, where an enactment or instrument expressly stipulates a particular age , for example, a statute specifying 21 for a particular qualification or entitlement , the Act does not override that specified age (s 5(3)). Businesses, banks, insurers, landlords and other contracting parties will need to reassess who can legally bind themselves without guardian or executor approval.
Courts and tribunals. Judicial and administrative decision-makers must apply the new default construction for terms such as "majority", "full age", and "minor" in enactments and instruments as mandated by s 5(2), subject to contrary indications. This affects capacity determinations, disputes about contractual enforceability, and statutory rights that pivot on majority. The courts are also constrained by the savings and exceptions in s 5(3), (4), (7), (8), and (10), and by the interpretation provisions in s 3.
Executors, trustees and guardians. The Act specifically treats certain existing orders controlling money payable to minors (for example trust directions, court orders relating to settlements) as if references to attaining the age of 21 or full age were references to 18 (s 5(6)). Executors and trustees administering settlements and distributions must therefore apply the lower age where the order or direction was in force immediately before the commencing day. At the same time, interests and estates to which absolute entitlement was gained before the commencing day are preserved (s 5(8)).
Employers and industrial parties. Section 5(7)(a)-(c) expressly excludes industrial awards, orders, determinations, apprenticeship instruments prescribing wages and conditions, and employment provisions from the operation of s 5. That means that where industrial law or statutory employment conditions continue to refer to the older thresholds, the Act does not automatically alter those rights and obligations. Employers and awards commissions therefore remain the primary decision-makers for employment-age rules that have not themselves been amended.
Legislative drafters and statutory administrators. Because s 5(2)(a) applies to enactments whether passed before, on, or after the commencing day, drafters of statutes and regulations must be aware that the default construction of majority-related terms is now 18 unless a contrary intention appears (s 5(2)). Administrators responsible for applying statutes and instruments need to decide, for each instrument and enactment, whether a contrary intention or an express age requirement exists.
Those concerned with wills and estates. Section 5(5) makes a specific saving for wills and codicils executed before the commencing day: a will executed before that day is not to be treated as made on or after that day merely because a later codicil confirms it. That provision affects estate planning practice and post-commencement execution and confirmation of testamentary documents.
Users of Commonwealth and other State laws. The Act’s definitions in s 3 narrow its reach by excluding laws of the Commonwealth and of other States from the phrase "laws of the State". Consequently, bodies whose rights and liabilities arise under Commonwealth law or other State law (including national superannuation regimes or federally regulated contracts) should not assume the Age of Majority Act changes those regimes. The Act’s application is to Western Australian enactments and instruments, as defined.
In sum, the Act affects persons approaching or within the 18-20 age range, their contracting counterparties, trustees, courts and administrative decision-makers, and statutory drafters, with specific carve-outs for industrial/employment rules and other preserved interests. The Act’s definitional limits and savings determine which categories of relationships and legal instruments are within its scope.