There is a growing divide between Perth's haves and have-nots, with research showing wealthier workers have enjoyed much bigger pay rises than the poor.
The Committee for Perth, a community group that commissioned the research, said the trend had led to a new cohort of "working poor" in WA.
The research shows that mean personal taxable incomes in WA grew between 40 and 70 per cent between 2005 and 2012 but the bigger increases were in the richer suburbs.
Peppermint Grove workers enjoyed the highest incomes - $179,248 in 2011-12 - as well as the steepest pay rises, with a 70 per cent wage surge over the seven years.
Workers in blue-ribbon Cottesloe got the second-biggest jump in pay at 69 per cent and those in Mosman Park had a 68 per cent rise.
Workers in lower socioeconomic areas had much smaller pay rises in the same timeframe.
Battlers in Wanneroo South - which had the lowest mean incomes in the State at $60,751 in 2011-12 - received increases of 45 per cent in this period.
Gosnells workers got an extra 40 per cent and those in Bassendean received another 41 per cent over the seven years.
Committee for Perth chief executive Marion Fulker said the research showed a clear trend across the State that was widening the gap between rich and poor.
"Perth has always been a city where if you are gainfully employed you can afford a reasonable standard of living," Mrs Fulker said.
"With the recent cost increases in housing and household expenses the pinch gets felt across the community, but particularly for those on fixed incomes, on pensions and working part-time."
The research, by the University of WA, showed the State's mean personal taxable incomes were, at nearly $76,000 in 2012, higher than in any other State in Australia.