National Party MP Steven Joyce has confirmed he made a formal complaint to NBR about a column which was highly critical of him, saying it was "highly defamatory."
The column last Friday was by right-wing commentator Matthew Hooton following Joyce's unsuccessful bid for the leadership of the National Party.
Joyce said the column was "highly defamatory and includes a significant number of factual inaccuracies".
It is understood the letter from Joyce's lawyers sought a retraction and apology.
NBR has not yet agreed to do either and it is understood any legal action Joyce took would be defended, including calling National MPs to give evidence in court should it get that far.