In a telephone interview on Wednesday with CBC News from Paris, where the NDP leader is on a three-day work trip, Mulcair denied ever making the comments, which drew criticism from the Conservatives and Liberals alike.
Mulcair was asked about the political reaction to his comments and whether it was appropriate for him to say the accident in Lac-Mégantic was "another case where government is cutting in the wrong area.”
"I never said that," Mulcair said.
The NDP leader said he was "more concerned than anything about the human tragedy that was involved."
Mulcair went on to explain that what he did say was "that the Conservatives have failed to protect the public in key areas such as maritime search and rescue, such as food inspection, and such as railway. Because when you start cutting the budgets for railway inspections, you're not taking care of public protection."
CTV News reported that "Mulcair, who visited Lac-Mégantic following the derailment, said the accident was 'another case where government is cutting in the wrong area.'" Mulcair was in Lac-Mégantic on Sunday.
In the video, Mulcair is seen saying: "We've got to get beyond this new system that they seem to be wanting to put in place of self-regulation. Governments have to regulate in the public interest, nothing more important in what governments do than taking care of the safety of the public."
"And this is another case where the government has been cutting in the wrong area," Mulcair said in the video.
Mulcair 'prudent' not to draw the link
But on Wednesday, Mulcair was adamant "it's not a quote from me."
"I've been prudent not to draw the exact link," Mulcair said.
Andrew MacDougall, the director of communications for Prime Minister Stephen Harper, took to Twitter on Sunday following Mulcair's comments saying: "The people of Lac Mégantic have experienced an unspeakable tragedy and we do not yet know its cause. It is grossly inappropriate for Mr. Mulcair to put politics ahead of the people of Lac Mégantic."
Former interim Liberal Leader Bob Rae also took to Twitter to show his disapproval with the NDP leader's comments saying: "Tom Mulcair blaming Harper for the tragedy at Lac Mégantic is a new low. And as you know, I'm no fan of Mr. Harper's politics."
But again Mulcair was unequivocal, telling CBC News on Wednesday: "You won't find that quote from me. That's an amalgam, and a shortcut. And it doesn't reflect anything I said."
"I never referred specifically to the prime minister in that case. It's just simply not true," Mulcair said.
"What you're hearing from me is, it's my job as the leader of the opposition to hold the government to account. When you start having situations where the public protection is compromised because of cuts whether it's in the field of food inspection, whether it's in the field of maritime search and rescue, or the field of railway safety, we're doing our job by asking whether that made any sense for the government to be cutting public protection. That's what I'm saying."
Harper and Liberal Leader Justin Trudeau also traveled to Lac-Mégantic since Saturday's train derailment and a series of explosions killed 15 and destroyed the heart of the small town in Quebec's Eastern Townships.