NAMA is being asked to explain how it valued its Northern Ireland property portfolio for sale.
The agency's Chairman and Chief Executive are appearing before the Dail's Public Accounts Committee today.
Around 850 assets were sold in one lot for over 1.5 billion euro last year.
But in the Dail last week, Independent Deputy Mick Wallace claimed they were worth in the region of 4.5 billion - a claim NAMA strenuously denies.
The agency says it sold the assets for what they were worth and not a cent less.
The PSNI has launched a criminal investigation into activities relating to the purchase.
PAC Chairman Deputy John McGuinness says the police investigation changes the committee's immediate plans........