A study by the Simon Communities has found a severe shortage of properties for people who rent using Rent Supplement and Housing Assistant Payment payments.
The charity said increases in rent payment limits introduced in 2016 were no longer effective.
The study, carried out in May, found that just 8% of properties available to rent were within the Rent Supplement and HAP limits.
It also showed that in eight out of the 11 areas examined, there were one or no properties available within rent payment limits.
Simon Communities said this was the lowest since Rent Supplement and HAP limits were increased in July 2016.
The number of properties available to rent within the payment limits in regional towns has decreased from 13 properties in February this year to six properties in May.
The report also found that there were just 530 properties available to rent with no income limits across the 11 locations compared to 1,150 in 2015.
The charity has said the limits for HAP need to be increased to address the shortage of properties available.
Speaking on RTÉ's Morning Ireland, the Simon Communities national spokesperson Niamh Randall said supply was decreasing outside of urban centres with only six properties available.
Of the properties available to rent within the rent support limit, she said there were only four available for single people and four available for couples.
Ms Randall said availability of properties for single people was of great concern as 44% of those on social housing waiting lists were registered as single.
She said targeted measures were needed to address the issues, in particular in the construction of new properties to meet the needs of everyone in search of somewhere to live.
Ms Randall said housing benefit payments could be increased but only on a case-by-case discretionary basis.
She added that on a long-term basis, this was not an adequate policy solution given what those in search of a property had to undergo.
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Meanwhile, the Department of Housing has said that the HAP scheme was "working very effectively" and was available in all 31 local authorities.
It also said that the report by the Simon Communities "is based on data from a single website which does not actually show the true picture".
The department said that last year "just under 18,000 additional HAP tenancies were supported or, approximately 350 new households per week and that has not dropped for 2018."
Fianna Fáil's Spokesperson on Housing, Darragh O'Brien has said housing benefits should only be a short-term stop gap measure but that the Government is using it as a solution.
Speaking on RTÉ's Today with Miriam Mr O'Brien said there was a massive over-reliance on the private rental market.
He said that since 2011, over €4bn had been spent on the private rental sector through rent allowance and housing assistance payment.
In response to the statement from the Department of Housing, Mr O'Brien said the Simon report showed a very clear trend that there are fewer properties available to people on HAP and in general there are fewer rental properties available full stop.
He said the department should "wake up and get that the reality of the situation is that the private rental market cannot sustain this level and can't take up the tab, effectively for all of those who are out there looking for properties."