The former minister for transport, Mr Brennan, has denied he threatened to resign his Dáil seat when it emerged in meetings with the Taoiseach, Mr Ahern, that he was not assured of a Cabinet seat in last week's reshuffle.
Mr Brennan's official spokesman said there was "absolutely no truth" in reports in the Sunday Business Post and Sunday Tribune yesterday, which said he had threatened to resign from the Dáil if dropped from the Cabinet.
"At no time did he threaten to resign his seat, or that kind of thing," the spokesman said.
While a number of TDs said in the immediate aftermath of the reshuffle they believed Mr Brennan had threatened to resign, such claims were denied on Wednesday night by several sources close to Mr Brennan.
The Taoiseach's spokeswoman declined to comment on Mr Ahern's engagements with Mr Brennan on Tuesday and Wednesday, when the outgoing minister for transport was demoted to Social and Family Affairs. However, separate Government sources said they believed that Mr Brennan did not threaten to resign or raise the idea of resigning.
Mr Brennan is known to be deeply unhappy to have been removed from transport, after only a little over two years in the post. He was asked at his first meeting with Mr Ahern on Tuesday to explain why he should hold on to his job and left that meeting with the impression there might not be a place for him in the Cabinet.
While it was only on Wednesday morning that Mr Ahern offered him the Social and Family Affairs post, Mr Brennan demanded an economic job before accepting the portfolio when the Taoiseach made it clear that his only alternative was to leave the Cabinet.