Fianna Fail leader Micheal Martin has branded an attack by former Taoiseach Bertie Ahern on party grassroots as "unacceptable".
Mr Ahern described some members of cumainn - local party branches - as "useless good-for-nothings".
In an upcoming documentary with TV3 on the demise of Fianna Fail, he said rank and file were having "tea parties" during the 1970s and 1980s about the state of the world.
"But as far as building up the Fianna Fail vote in these areas, they were useless," he said.
Staunchly defending his own stewardship of the party leading up to its electoral meltdown, Mr Ahern singled out a cumann in Dublin's north inner city during the 1970s, who he said were not northsiders and were frightened of crossing the Liffey.
"They were afraid to come into Sean McDermott Street, to drive through it, never mind canvass it," he said.
"So, quite frankly, they were a bunch of useless good for nothings."
Reacting to the remarks, Mr Martin said he would wait to see the documentary but would be appalled to hear the party grassroots described in such a way.
"That would be a completely unacceptable comment to make of the members of the party," he said.
Mr Martin said he had great respect for every member of the Fianna Fail party and was trying to encourage people to enter public life.