Peter Robinson did not raise concerns about controversial former Nama adviser Frank Cushnahan's involvement in the agency's Project Eagle sale, it has been claimed.
And the former First Minister said he had been unaware of any proposals to pay a success fee to the high-profile businessman.
A letter from a firm of lawyers to Irish TDs claims the former First Minister was told of a proposed advisory role for Mr Cushnahan on behalf of Pimco, a US company that bid for Nama's Northern Ireland loan book, in May 2013.
Mr Cushnahan sat on Nama's Northern Ireland Advisory Committee (NIAC) at that time.
It emerged two years later that he was alleged to be in line to share in a proposed £16m success fee if the deal went ahead.
The letter to TDs came from Brown Rudnick - a law firm working with Mr Cushnahan and Pimco - and says neither Mr Robinson, nor Stormont Finance Minister Sammy Wilson, "raised concerns" at Mr Cushnahan's involvement in the sale process at the May 2013 meeting.
According to the letter, Mr Cushnahan said he had an unpaid voluntary role with the NIAC - but he didn't say or imply that he had access to confidential information in this role.
Mr Robinson last night insisted he had no knowledge of the alleged fee to be paid to Mr Cushnahan until it was revealed at the Dail's Public Accounts Committee (PAC) in the summer of 2015.
Ultimately, Pimco exited the sale process in March 2014 after it informed Nama of the alleged fee to be shared equally between Mr Cushnahan, Brown Rudnick and another law firm. The high-powered Dail committee is probing Project Eagle after the Republic's Comptroller and Auditor General found that a probable loss of £190m (€223m) was incurred in the €1.6bn 2014 deal.
Brown Rudnick declined the Dail PAC's invitation to appear before TDs, citing ongoing investigations into Project Eagle in the UK and the United States.
The firm insisted it acted with "the utmost good faith and propriety at all times" throughout its involvement in the Project Eagle sales process.
In a statement to the Irish Independent last night, Mr Robinson referred to the ongoing National Crime Agency probe into the Project Eagle sale, saying there is a "need to let professional investigators deal with the issues relating to Nama".
He said he wasn't aware of the alleged fee arrangement with Mr Cushnahan at the time of the May 2013 meeting.
"As I informed the Northern Ireland Assembly finance committee public hearing, I had no knowledge of Mr Cushnahan receiving or expecting a success fee nor indeed any other fee until the issue was publicly raised," Mr Robinson said.
Last night Mr Cushnahan's legal representatives said that their client was not prepared to comment on "selective extracts" from correspondence he had not seen.
"My client is satisfied that his business discussions have been bona fide and lawful," the spokesman added.
Republic of Ireland
The international firm that advised NAMA on the sale of its Northern Ireland loan book was treated like an “eejit” and a “patsy” prior to the €1.6 billion property transaction, the Public Accounts Committee (PAC) has heard.
First Minister Arlene Foster has been urged to "pressure" Peter Robinson into appearing in front of the public accounts committee in Dublin to give evidence on the Nama scandal.