Thousands of Irish people are every day forced to compete in a "desperate lottery" for expensive flats which are often in poor condition, according to the Simon Community.
The national director of the Simon Community, Mr Conall MacRiocard, said the issues of affordable rent and stability were "fudged" in the Commission on the Private Rented Residential Sector's latest report, which was published on Thursday.
Mr MacRiocard welcomed the report's vision of the sector as providing secure, affordable, good-quality accommodation, but said the reality was very different. He claimed some tenants had seen rents double and even treble in recent years.
"Unjustified rent increases directly cause homelessness among the most vulnerable: people in low-income unemployment, the unemployed and, increasingly, older people who lack family or social supports," he said.
A process of `index-linking' rents to inflation would guarantee security for tenants and a reasonable return for landlords, and he called for the introduction of rent guarantee schemes to improve access and stability. Mr MacRiocard said Ireland compared unfavourably to its European neighbours in terms of its housing policy.
