Already done, but they have 14 days to correct.
In NSW you can apply to Tribunal (if your tenant has a history of paying late) to get an order where if you send another 14 day termination notice (for rent arrears) the tenants have to move out regardless if they pay up before the vacate date. You'll have to show tribunal your late notices, communication notes and payment plans etc to help get this order.
Atleast if you got this order you would scare your tenants and hopefully they don't fall behind anymore! And if they do, the next 14 day termination notice will stick regardless if they pay up.
By law, can we (as a landlord) do this?
It would be awesome, if the direct debit can be implemented.
As a Private Landlord I think best thing to do at the moment is get your tenants to 'schedule' the payments. They can by going into their internet banking (or in branch) and setting the schedule. This has worked for me in the past.
We are currently building our 'Rent Collection' module now for my business. It wont be ready for while yet (possibly 6 months) as there is a lot to it but it will have Direct Debit.