Focus Ireland, which helps the homeless, has said it is finding it "nearly impossible" to find private rented accommodation.
A report from its Flat-Finding Service indicates users are being severely affected by the worsening accommodation crisis. This follows the findings of a study, released last week, which showed that rents in Dublin had increased by 50 per cent in the past three years.
Focus Ireland offers a free accommodation-finding service to people who are homeless or are at risk of becoming homeless due to rising rents in the private sector.
The group indicated yesterday that the long waiting list for local authority housing had exacerbated an already critical situation by forcing people on low incomes to find accommodation in the private rented sector.
Its own research showed a 17 per cent increase in local authority waiting lists since 1999, to 45,645.
The figure represented "well over 100,000 men, women and children (who) have no proper home to go to every evening", it said.
It pointed out that "although a family with two or more children will be assisted with rent allowance of up to £850 a month for a three-bedroom house, or, in the case of single people, about £76 a week for a bedsit, the agency cannot find property owners who will offer accommodation to these people".
Focus Ireland's chief executive, Mr Declan Jones, criticised a recent report from the Commission on the Private Rented Residential Sector for failing "to address the growing problems facing people on low income trying to enter (and remain in) the private rented accommodation sector".
He appealed to property owners to contact the agency's flat-finding service at 016712555.