NAMA say they have sold enough land to build 50,000 homes since 2011, but only 3,000 have actually been built.
Their annual report shows just 6% of that land sold has been developed.
Announcing profits of €1.5bn for 2016, NAMA said it offered councils nearly 7,000 houses or apartments over four years.
Dublin has seen the largest number of social houses from the agency, 901, another 445 in Cork, 228 in Galway and 172 in Kildare.
NAMA also said there were only 11 ghost estates left in the country at the end of March this year, down from 332 in 2010.
As the agency said it is on course to make €3BN by the time it finishes its work, it also revealed it funded the construction of 4,840 new homes over the last three and half years.
Another 2,064 are being built and there is planning permission for another 1,114 new homes.
When asked why NAMA had not built more homes over the past few years, CEO Brendan McDonagh, said that legally they could not.
He said: "The reality was that the sales revenue wouldn't even cover your building costs, so there is a lot of this talk saying NAMA should have been building houses during 2010, 2011, 2012 and 2013.
"The reality is that we couldn't, the legislation would have prevented us.
"Section 10, you could not build something when you know you are going to lose money, but we have been funding the building of houses instead when it made sense to do so."
"It is important to emphasise that achievement of this surplus will depend on our ability to extract maximum value from the residual portfolio which is secured by many low-value assets which require extensive workout," he said.
NAMA said it has a target to build 20,000 new homes by 2020 if they are commercially viable.
The agency borrowed €31.8bn to take loans linked to property developments and land speculation off the books of the main Irish banks.