In Australia, landlords can increase rent, but there are rules governing how and when they can do it. Generally, the notice period for a rent increase is 60 days, and the amount of the increase must be reasonable and in line with the market rate. It's important to check your lease agreement, as it may specify terms related to rent increases. If you have concerns about the increase, consider discussing it with your landlord or seeking advice from a tenancy advice service. For more detailed information, you can visit the relevant state government website or contact your local tenancy authority.