The rental crisis has been exacerbated by a surge in vacant properties, with nearly one in 10 WA homes sitting empty, according to the WA Housing Coalition.
Analysis of census data by the WAHC shows 66,231 vacant residential properties in WA, which is 9.6 per cent of the total housing stock.
This is up from the 48,600 in 2006 when the vacancy rate was 8 per cent.
WAHC executive officer Barry Doyle said the trend was partly because WA had one of the highest rates of second-home ownership in the world.
These owners could afford to keep second properties empty for personal use as holiday homes or during long renovation projects.
Some investors were able to afford to keep properties for their capital gains, without the hassle of entering the rental market.
But in a sign of Perth's two-tier economy, this trend was restricting the supply of accommodation and pushing up rental costs.
Mr Doyle called on the State Government to investigate incentives to encourage homeowners to bring vacant properties to the rental market.
Greens Senator Scott Ludlam has called for a convert-to-rent loan scheme to help landlords bring properties up to rental standard.
Cabinet-making apprentice Jessica Bradshaw, 19, said she had applied for more than 50 rental properties since March but was rejected repeatedly because of her age and low wage.
While she is now in temporary community housing, she fears she will have to return to living in a tent if she cannot secure accommodation soon.
Welfare worker Nicole Cooper, who has worked with homeless people for a decade, said she was living in her car partly because rents were too high.
"Homelessness is only going to increase because no one can afford to pay these rents," she said.