Donegal Senator Brian O'Domhnaill has said he will have more to say about NAMA in the Seanad tomorrow.
It's after the agency wrote to him asking him to either substantiate or withdraw comments he made in the house last Wedneday.
Senator O'Domhnaill accused Nama of acting disgracefully, and said it is time it was fully investigated.
He called on Finance Minister Michael Noonan to come into the Seanad and address mounting concerns about the levels of transparency at Nama.
Senator O'Domhnaill claimed two former senior officials that were involved in HSBC, a bank which violated anti-money laundering rules in the US are now employed by Nama.
However, in its letter to Senator O'Domhnaill, Nama says this is "totally incorrect". The letter also rejects claims that a former official now works for a company he had dealings with while employed by the agency.
At the weekend, Mr O Domhnaill told the Sunday Independent he rejects what he termed Nama's "aggressive" letter and likened it to an attempted gagging order.
He not only would he be ignoring the demands to substantiate or withdraw, he would be "going on the attack" when the Seanad resumes tomorrow.