Can Landlord Charge Me Utilities?

My original tenancy agreement in Sydney says rent costs include gas, electricity, and water. The property is not separately metered. There is a small clause later down that says water will be paid if separately metered. Now the landlord wants to separately meter. Can they ask for me to pay utilities? Even if the lease agreement says I don't need to pay? If they can ask me to, how much notice must be given? None?