Landlords would only be able to increase rent once every two years and may face a cap on the amount they can hike it by under sweeping planning and housing reforms being considered by the Andrews government.
Melbourne already has a defined urban growth boundary, but it still leaves the opportunity for a lot of low density fringe suburbs, which makes the provision of infrastructure and services cost prohibitive.
Hopefully the push towards 70% established/30% new areas will help address urban sprawl and get people living closer to services.
Melbourne has had various growth boundaries since I can remember. It also has plans for an airport rail. Both of these are fairy tales waved around by politicians occasionally and them dumped after the elections.