Independent TD Mick Wallace said he travelled to Asia last weekend to collect emails and documents from a businessman which will help show the Project Eagle sale was the biggest financial scandal in Irish history.
“Within a short time of Frank Cushnahan being appointed to Nama, he was peddling assets belonging to Nama to foreign parts,” Mr Wallace told the Dáil.
“Tughans were involved, the Japanese bank Nomura were involved, who were later the main financier for Cerberus’s purchase of Project Eagle. Nama, from start to finish, stinks from high heaven.”
Nama sold the collection of Northern Ireland property loans, known as Project Eagle, to US investment fund Cerberus in April 2014.
Another US company, Pimco, said it pulled out of an earlier bid after it was asked for a “success fee” or fixer payment of £15m for three parties behind the scenes.
The money was to be shared by Mr Cushnahan, US law firm Brown Rudnick, and Ian Coulter, a managing partner of Tughans, a Belfast law firm subcontracted to assist in the deal, Pimco told a parliamentary committee probing the sale.
Mr Cushnahan was formerly a Nama adviser on Northern Ireland, on the recommendation of the DUP.
All parties have denied any wrongdoing.
In the Dáil, Mr Wallace demanded that the board and executive of Nama be suspended until a full State inquiry is launched.
“It was not a competitive process, it was a scam,” he said.
“Nama have undersold a massive slice of this country to US vulture funds for a fraction of its value. They are contributing in a serious way to our housing crisis. They are not part of the solution to the housing crisis, they are part of the problem.”
Mr Wallace read some of the emails he said he collected from the businessman in Asia.
One dated, December 2010, which he said was from Mr Cushnahan, read: “There are very substantial opportunities for major returns to be made for anyone who can access international and institutional funds to acquire blocks of development assets from either development or agency itself.”
Another email from an unnamed person read: “ “Frank will ensure that only people with the highest integrity at government level will be involved and the returns look very, very good.”
Another refers to “acquisition success fees”.