The chief executive of National Asset Management Agency (NAMA) says there is an issue with developers hoarding land waiting for a better return.

Brendan McDonagh 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 is 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.

It has also been claimed by NAMA that local authorities and housing agencies have turned down over 2,500 housing units.

The number of properties turned down is roughly the same as the number of families currently in emergency accommodation.

Barry Cowen of Fianna Fáil wants an explanation.

Earlier, NAMA chairman Frank Daly told the committee that 88% of its housing stock has been sold to individuals and not vulture funds.

But he has warned that just 6,000 of the more than two million housing units in the State are in its portfolio.

But says the vast majority of these are already occupied.

Mr Daly says plans by NAMA to deliver 20,000 units by 2020, will only be one part of the solution that is needed.