As Michael Yardney points out in this article here, this is simply being driven by supply and demand: vacancy rates in the inner west are lower than 1%. That is an extremely low vacancy rate.
Sydney's eastern suburbs have a similar low-vacancy dynamic and rents will probably continue rise there too, though property value growth might be more unlikely in the more expensive east.
In fact, Metropole manage several of my properties and re-let one of them to a new tenant within 24 hours of listing it. So, yes, there's plenty of rental demand out there.
Predictably, the news out of Melbourne is less promising with vacancy rates being higher, and Melbourne values having boomed in recent years.
Photo: Sydney's inner west (well, a bit of it!).