Finance Minister Michael Noonan says anybody with information on malpractice in NAMA should come forward.
Mr Noonan said there had been a full garda investigation ongoing and anyone with information was obliged to provide it under criminal law.
Links between foreign financiers and a former official in NAMA are contained in an extraordinary dossier being studied by the Garda Commissioner.
The official admits illegally taking highly classified information from the secretive organisation in revelations set to cause a political storm for the government.
Detectives at the National Bureau of Fraud Investigation have now been given the dossier and are set to interview NAMA officials and former employees at the agency in the coming days and weeks.
Among the serious allegations in the dossier, seen by the Irish Independent, are:
* The official told gardai he fed information from the agency to named individuals who should not have received it.
* He claims there were improper relationships with the agents of foreign tycoons who were seeking information on Irish businesses and individuals.
* It is claimed named NAMA officials had personal friendships with some of the agency's debtors.
The allegations are potentially crippling for NAMA, which is wholly owned by the State and is Europe's biggest property owner.
They could expose the secretive agency to serious litigation and unwanted scrutiny.
When asked about the revelations last night, a spokesperson for NAMA told the Irish Independent that he would not be commenting.
In the dossier being studied by detectives, the former official has claimed named officials in NAMA were also involved in improper behaviour.
Gardai have already interviewed the man who said: "I put my hands up to the gardai and told them it was a fair collar."
The former official, who has already been interviewed under caution several times by the Garda Bureau of Fraud Investigation (GBFI), admits gave information about an Irish businessman to his rivals.
It is also understood the former NAMA employee admitted to leaking sensitive information about this man, including details of his private life, property interests of his extended family and his banking facilities.
On December 11, the Irish businessman’s lawyers wrote to Garda Commissioner Martin Callinan informing him of the dramatic development.
They demanded that the latest investigations were, in turn, fully investigated. The GBFI has been investigating the ex-official since 2011.
It is thought the claims in the dossier were behind allegations in the Seanad yesterday that sensitive information had been leaked from NAMA, which had allowed developers to profit.
Senator Darragh O'Brien told the Seanad he had come into possession of information that would rock NAMA to its core.
The Fianna Fail senator claimed the information had been leaked to so-called ‘vulture funds', such as private equity firms and hedge funds, which have descended on Ireland and the rest of Europe since the downturn, seeking assets that have plunged in value and are now under-priced.
The agency had earlier issued a short statement in the wake of comments made by Mr O’Brien in the Seanad.
NAMA said that if Mr O’Brien had evidence, it had not been shared with the agency.
By Paul Williams