The Quebec Federation of Labour points to Quebecor Inc.'s stormy relationship with unions over the years as the reason it would rather have someone else become PQ leader.
Labour leader Daniel Boyer says Quebecor (TSX:QBR.B) decreed 14 lockouts over the years with Peladeau as controlling shareholder of the media conglomerate.
That kind of approach, according to Boyer, is incompatible with wanting to become leader of a political party that claims to be progressive and left of centre.
Peladeau responded by saying he wouldn't do anything different if the kinds of situations he faced in the past existed today.
He said his decisions were made to ensure the survival of his company during a time of massive change in the media industry.
"I did what I thought was appropriate in the circumstances," he said in Quebec City.
While Peladeau has not officially announced his candidacy, there is a report he will do so on Nov. 23 in Saint-Jerome, his riding north of Montreal. The new leader is chosen in May.
Boyer said he has serious doubts that Peladeau is about to become pro-labour.
"I heard him at a legislature hearing where he wanted to call into question the anti-strikebreaker provisions in Quebec's labour code," he said.
Boyer noted that federation members want a PQ leader who is "more social-democrat and more progressive."
"These people don't think Pierre Karl Peladeau as head of the party will be a valid alternative for workers."