ACT Rent Increase Laws: CPI Caps and Notice Periods Explained

The Australian Capital Territory (ACT) utilizes one of the most highly regulated rent increase frameworks in Australia. Governed by the Residential Tenancies Act 1997 and Residential Tenancies Regulations 1998, the ACT employs a "soft-cap" system tied to inflation to protect tenants from arbitrary, excessive rent hikes.

Disclaimer: This guide provides general legal information for educational purposes only and does not constitute legal advice. The "prescribed amount" calculation changes routinely. Always consult the ACT Revenue Office. Information last verified: March 2026.

The 12-Month Rule

A landlord in the ACT can only increase the rent if at least 12 months have passed since the tenancy began or since the last rent increase.

• This rule applies regardless of whether the tenancy is a fixed-term agreement or a periodic (month-to-month) agreement.
• If a lease agreement includes a clause allowing for increases more frequently than every 12 months, that clause is void and legally unenforceable.

Mandatory Notice Period

To legally implement a rent increase after the 12-month period, landlords must provide the tenant with a minimum of eight weeks' written notice before the increased rent takes effect.

The written notice must explicitly state:

1. The proposed new rental amount.
2. The exact date the new rent will commence.

The "Prescribed Amount" Rent Cap (CPI Linked)

The ACT does not have a strict, absolute percentage cap (like "no more than 5% ever"). Instead, it forces landlords to justify increases that exceed inflation.

The legislation establishes a "prescribed amount" for rent increases. This amount is directly linked to the Consumer Price Index (CPI) for housing in Canberra. (Historically, the formula was 110% of the percentage increase in the CPI for rents in Canberra plus a small buffer, but this specific calculation changes based on quarterly statistics).

The "Prescribed Amount" Rent Cap Rules:

1. If the increase is LESS than or equal to the prescribed amount: The landlord gives the 8-week notice, and the increase takes effect automatically. (A tenant can still challenge the increase at ACAT if they believe it is excessive given the property's declining condition, but the burden of proof is heavily on the tenant.)

2. If the increase is GREATER than the prescribed amount: The increase is automatically presumed by law to be excessive. The landlord has two options:

• Tenant Agreement: The landlord can get the explicit, written agreement of the tenant to pay the higher rent. If the tenant signs an agreement, the increase proceeds.
• ACAT Approval: If the tenant refuses or disputes the increase, the landlord must apply to the ACT Civil and Administrative Tribunal (ACAT) for approval.

ACAT Review of Excessive Increases

If a landlord applies to ACAT to justify an increase above the prescribed amount (or a tenant disputes an increase), ACAT will consider a range of factors:

• The rental rate of comparable properties in the ACT.
• The cost of running the property (e.g., significant increases in interest rates or strata levies).
• Improvements made to the property by the landlord.
• The state of repair of the premises.

If ACAT decides the increase is excessive, it will set a maximum rent that the landlord is permitted to charge for the next 12 months.

How Landager Helps

Calculating the exact prescribed amount based on quarterly CPI data is complex and risky if done incorrectly. Landager automatically tracks the CPI data for Canberra housing. We alert you 10 weeks before your 12-month anniversary and calculate the exact legal "prescribed amount" cap for your property, generating an ACAT-compliant 8-week proposed rent increase notice instantly.

Back to ACT Landlord-Tenant Laws Overview.