Fine Gael members of the Public Accounts Committee have voted against its final report on the sale by NAMA of its Northern Irish loanbook.
It is the first time since the Public Accounts Committee was established that a vote has taken place on a committee report rather than it being unanimously agreed.
It is understood several votes took place on aspects of the final report.
The loanbook, known as Project Eagle, was sold to US investment fund Cerberus for £1.2bn in 2014.
The Comptroller and Auditor General later found the sale incurred a potential loss to the taxpayer of £190m.
The Public Accounts Committee began hearings into the sale last year.
Fine Gael had objected to a finding that it was "procedurally inappropriate" for Minister for Finance Michael Noonan to meet the ultimately successful bidder Cerberus before the closing date for bids.
Fine Gael members wanted this changed to "not advisable" prompting a vote which they lost by eight votes to five.
The report is due to be published next week.
A spokesman for Mr Noonan said "as the report of the PAC is not yet published it would be inappropriate to comment at this time on reports of its findings or content."