Speaking on the The Business on RTÉ's Radio 1 with George Lee yesterday morning, Frank Daly said NAMA had generated nearly €13bn in revenue since it started.
The income came from rents and from disposals of assets and properties.
Mr Daly said the amount of investment was not confined to €2.5bn and that if there were commercially viable projects they would invest more.
He also said that to date NAMA has invested €0.5bn into the economy in commercial residential developments.
He said that NAMA had reached agreement with South Dublin County Council to buy the car park in the square in Tallaght with the view to developing the square.
He said that the development would create an estimated 300 jobs in the construction phase and 400 jobs on an ongoing basis as new shops and outlets move in.