Tribunal will look at the following to see if the rent increase is warranted so I would do up an email to the agent and include points of the following and say why you think it's excessive and that you would like them to discuss with the landlord :
- Look at similar properties in your area (at least 3), take photos, and gather evidence of the rent for the properties (through real estate agent listings ( especially from your agency) or statutory declarations from current tenants – newspaper clippings are not enough).
-Make a list of repairs not done by the landlord
- Make a list of repairs done by the landlord (if any).
- Make a list of all rent increases since you lived at the premises.
-Gather receipts for any work you have had done to the premises with the landlord’s consent.
- Take photos showing the condition of the premises.
- Find out ( if you can) if council, mortgage, insurance and water rates have increased in recent years – get this in writing if possible (in case the landlord claims increased charges as a reason for the rent increase).
If you can prove through the above the increase is not warranted you will have a strong case if you had to go to tribunal ( you have 30 days to dispute the increase)
As pp has said we need confirmation from landlords for rent increases ( ours are reviewed yearly )