Former treasurer Peter Costello has warned of widespread hardship when the property sector's rapid growth inevitably slows in an economy that already has nervous consumers whose real wages are falling.

At a property industry event in Sydney on Wednesday, Mr Costello said Australia's luck was "beginning to run out" and the country had big questions to grapple with in the near future.

"We've got anxious consumers who are saving money, with real wages falling in a country where incomes have peaked.

"And they're distrustful of the political class where consensus is breaking down. We need to work out how to put things back together."