Green Party leader John Gormley has rejected suggestions that the Nama projections revealed by the Government earlier this week were the work of Fianna Fáil ministers.
Mr Gormley insisted last night that the figures had been prepared and assembled independently on behalf of the Government.
He also insisted that Irish taxpayers would be protected in the legislation setting up the asset management agency by ensuring the banks pay a levy if Nama does not make a profit.
The business plan unveiled by Finance Minister Brian Lenihan predicts that the agency will have made a profit of €5.5bn by the time it concludes its work in 2020.
It predicts that developers will default on just 20% of the €77bn in bank loans that are due to be bought by Nama and that the remainder of the loans will be repaid in full with interest.
Speaking to members of the Heritage Council in Tullamore last night, Mr Gormley said this assessment was carried out by independent economists and he believed the figures do stand up to scrutiny.