The National Asset Management Agency (NAMA) says it does not have the units available in Dublin to solve the crisis of families in emergency accommodation.
The agency has also revealed to the housing and homelessness committee that more than a third of the properties it offered to local authorities for social housing were turned down for various reasons.
They revealed that of more than 6,700 housing units they offered to local authorities, 2,500 were deemed not suitable.
Issues included them being not finished, not in the right area, being too big or too small or Government policy refusing to allow a denisty of social housing in a single development.
The agency was also asked if it had 800 to 1,000 units in Dublin that could immediately ease the crisis of people in hotels and B&Bs.
NAMA's Chief Executive Brendan McDonagh said: "We have 6,000 completed residential units left in our portfolio. About 99% are rented by the private sector.
"We don't have 800 to 1,000 units."
Meanwhile, six days into the new Government the Cabinet sub committee on housing met for the first time today and Ministers have promised a plan to deal with the crisis within 100 days.
Mr McDonagh says there is an issue with developers hoarding land waiting for a better return.
The chief executive has told the Oireachtas Housing and Homelessness Committee that since the start of 2014, they have sold land that could provide up to 20,000 units, but just 5% of that has so far been delivered.
He said that while there are a number of issues around planning and the density of housing, he believes owners and developers are waiting for a better return.