Our last rental in Adelaide was a new build, and was also very dirty when we moved in with a number of unfinished jobs waiting to be done, like washing line and TV aerial installation.
I complained to the agents, and advised them that I would not pay the full rent until things were put right, and then deducted money from the rent for doing the cleaning.
The agent seemed fully understanding, and advised the owner of our intentions who then accepted the position. After a couple of weeks everything was okay, so full rent was paid. We had to break our lease early, but the agent was very helpful regarding re-letting, and there were no hard feelings expressed towards us, so be firm if you are palced in this position.