In Sydney, NSW landlords generally can increase rent only once every 12 months and must give at least 60 days’ written notice. NSW does not set a standard percentage cap, but a tenant can challenge an increase they believe is excessive through NCAT, usually within 30 days of receiving the notice. The agreement may also contain specific rules for rent increases during a fixed term. Check the current guidance on the NSW Fair Trading website or seek tenancy advice before acting.