A Stormont watchdog is to take legal advice on compelling Nama to appear before it.
The Finance Committee is investigating a £1.1bn deal to sell the organisation’s Northern Ireland property loans.
Nama and all private firms involved in the Northern Ireland assets sale have denied wrongdoing.
Committee chairman Daithi McKay said: “At today’s meeting of the Finance Committee inquiry into the sale of Nama’s northern portfolio we agreed in principle to use the committee’s power to compel witnesses to come to the inquiry.
“It was agreed to compel both Nama and the permanent secretary of the Department of Finance and Personnel to attend the inquiry.”
The committee also agreed to invite US investment firm Pimco, which considered buying the properties, to come to the inquiry to answer questions on its involvement in the transactions.
Nama sold the portfolio to US firm Cerberus last year.
Allegations were levelled in the Dáil recently by Independent TD Mick Wallace.
Using parliamentary privilege, Mr Wallace alleged that £7m in an Isle of Man account linked to the deal was “reportedly earmarked for a Northern Ireland politician or political party”.
A lawyer involved has denied the money was intended for a politician or relative of a politician.