First off, I advise any tenants and, indeed, landlords to go to the Tenants Union website (tenants.org.au) where you will find a stack of fact sheets covering both tenants and landlords obligations. You might want to have a look at this one which is about locks and security.
Regarding the fly-screen, I suspect you might need to install that yourself and then make sure any damage to the window is repaired before you leave. Have a look at this Factsheet from Fair Trading about the best way to proceed.