that article hit a few nails on the head:
"Across greater Melbourne, more than one in four apartment project approved is located in the City of Melbourne, according to data from the Australian Bureau of Statistics.
Dr Wilson said data showed the oversupply was in the CBD, where the market had been flat over the past decade.
As a substantial number of apartments work their way through to completion, new residential zones implemented by councils in the city's inner and middle ring suburbs have made it harder for developers to build medium and higher density housing."