For Sydney to hit a million, prices would need to rise by about 11% during 2015. If the dollar falls then there could be increased demand from overseas, and a couple of interest rate cuts could inflate things further...
So I'd agree that it could get there by the end of the year.
But the article that Shadow linked to is incredibly bearish for something coming from the real estate industry. I'm inclined to agree with its sentiments, see my tagline, and I believe that there's a real risk of a blow out. Sydney property prices are in the "doesn't end well" zone when compared to markets in recent history.
That said, I spent the last few years living in London, and the housing market there really doesn't make any rational sense. So what do I know?