Rent increase rules in 2026 depend on your Australian state or territory, whether you have a fixed-term or periodic agreement, and what your lease says. Generally, the landlord must give written notice and can only increase the rent at permitted intervals, but the timing and notice period vary between jurisdictions. If the increase seems excessive, you may have options to challenge it through the relevant tenancy authority or tribunal. Check your state or territory’s official residential tenancy website, or contact a tenancy advice service, for the rules that apply to your address.