The landlord or agent must tell you why they want to come to your house. If they do not tell you why, you should ask for the reason. They can email you, send you an SMS or a letter telling you the reason why they want to come and what date and time they want to come....
This is the chapter about renting from the Northern Territory Law Handbook.
This factsheet talks about some of the common problems people have when they rent a house.
This factsheet tells you how much notice your landlord must give you if they want to come into your house.