The Sydney market is very much in full peak of cycle. It is a time for portfolio builders to perhaps consider selling an IP or two (if they are in a later stage of their investment journey), not to be acquiring property in this market.
There are other dynamics at play that are influencing values, yes; especially the influx of local and foreign investors. The ones I feel for are home buyers. Specifically; house buyers. First home buyers are usually getting units, not houses. Well, in a couple of years in sydney when all those dozens of cranes in every compass direction come down, and in their places, new unit towers stand complete, first home (unit) buyers, so, singles, Dink's, and the like, will have their pick of well priced units in great locations (that's my personal belief, totally happy to be refuted and challenged on that!).
But not all FHB's are unit seekers. Some genuinely need houses with land. Those with more than one kid, big dogs, or a yearning for more space and a garden etc., those buyers will have a tough time, no matter how many new apartments flood the market.
Sydney is a unique market because of geography. The greater city limits in every direction, meet national parks. This is a physical barrier to making more land available. It just can't keep sprawling forever because it'll eventually hit the 'fences' that are national parkhis makes the scramble for 'land' fierce. It is a finite resource in this city (a la Singapore). Whilst other capitals have their fair share of national parks, they aren't literally ring-fenced with them like Sydney is.
Add to that, the massive chunk of land now designated to Badgery's Creek Airport (god I hope they give the actual airport a better name than 'Badgery's Creek' in the end), which has just swiped a big chunk of greater suburban available land, and land will continue to be the expensive, scarce resource that it is, in Sydney.
Investors should tread carefully, and FHB's.. Well I dont know what advice to possibly give them in the Sydney market other than 'um... Request a transfer from work to say Brisbane or Adelaide and live a happier, less stresaed, better quality, and cheaper life there instead'