When Reserve Bank governor Glenn Stevens says slower growth in house prices would be good for the economy, he's right in more ways than one.

Mr Stevens has been attempting to jawbone investment in the housing market down for some time, over concerns about the potential for a damaging correction down the track. Fair enough. But rising house prices are threatening Sydney's economy in a far more fundamental way: by locking a generation of productive young people out of town.

When young people can't buy a property in Sydney, it's a problem for the whole of society. Credit:Louie Douvis

We are now at a point where prices are so high that most young people can't get a foothold. Sure, there's a lucky minority who can hit up the Bank of Mum for a hundred thousand dollars or two, but it is impossible for most to save an adequate deposit.

With high rent prices forcing young people to jettison a higher and higher percentage of their weekly income the problem becomes intractable. It now takes more than nine times the average salary to buy a house in Sydney. Just a single generation ago it took three.