The Social Democrats' party think-in has been told that landlords in just seven of the 1,100 rental properties in Dublin advertised on property website Daft.ie would accept payment under the Housing Assistance Payment scheme.
Ahead of the new Dáil term, the party is setting out its priorities for Budget 2018 at the event in Dublin's Smock Alley Theatre.
Carly Bailey, the Social Democrats local area representative for the Firhouse-Ballycullen area in Dublin, has described how difficult it is for families from "the locked out generation" to find accommodation.
She said that she lost her home in 2013 and spoke about how being in mortgage arrears is "incredibly difficult".
She said there are currently 32,000 homeowners who are more than two years in arrears, and said that 10,000 of those debts are owned by vulture funds whose sole aim is to make a profit on these homes.
Commenting on the number of landlords willing to accept the HAP payment, she said: "That is why so many people are ending up in emergency accommodation."
The Social Democrats is using its half-day think-in event to explore issues faced by the "locked out generation - those experiencing increasing insecurity when it comes to finding homes to buy or rent".
Meanwhile, the party is also advocating phasing out the special 9% VAT rate for the tourism and hospitality sector over three years, to bring it back to its original 13.5%.
It was reported in July that a Department of Finance briefing document advocated that Minister for Finance Paschal Donohoe should increase the special 9% VAT rate.
The department suggested a return to the 13.5% rate would yield €500 million a year.
The Social Democrats today joins bodies such as the Irish Congress of Trade Unions in calling for the abolition of the VAT rate.
Party co-leader Róisín Shortall said: "The special VAT rate of 9% has served its purpose - tourism in Ireland is booming and last year a record 8.8 million overseas visitors came here.
"Increasing VAT on the hospitality sector would free up some €500-€600 million a year.
"Some of this money could be redistributed to support the tourism sector in other ways. It could also fund initiatives to support small and medium size enterprises and to finally ensure proper broadband coverage around the country, which is crucial for business growth and jobs.
"It would also increase the pot of money available for Budget 2018 and subsequent budgets. That would in turn allow for significant investment in healthcare, with the roll out of the Sláintecare ten-year reform plan, as well as measures to ensure that primary education is genuinely free, and to fund vital infrastructural projects."