Sydney regions, with the exception of the eastern suburbs, have reached their highest median price ever, according to Australian Property Monitors.

The regions that demonstrated the biggest improvement on the previous peak in 2011 are in outer Sydney, as well has Canterbury-Bankstown, which have median prices of more than 10% above the 2011 high.

Other strong performers include the inner west which recorded a 9.5% increase and the upper north shore, at 8% over the same period.

However, the eastern suburbs as a collective are still 0.4% below record price point, despite prices rising strongly this year.

The growth has led to record prices in outer suburbs like Fairfield, which, according to News Ltd, had its first sale over $1m this month: a new seven-bedroom house. A Mount Druitt property recorded a $780,000 sale this month.

But one analyst thinks these strong results could be nearing an end. Managing director of SQM Research, Louis Christopher, predicted in 2011 that Sydney's outer suburbs would outperform the rest of the city.

''I still think it'll be strong for the next six months,'' he said. ''But the more it grows from here, the bigger the chance that if we get an interest rate rise that this area will underperform for a period of time.''