LONGUEUIL - The Parti Quebecois must become an engine of change where ideas flow freely, said Bernard Drainville at the launch of his campaign for the leadership of the sovereigntist party.

The MNA for the Marie-Victorin riding in Longueuil has officially launched his bid to head up the party at a rally.

The contender to succeed Pauline Marois made a plea for secularism, addressing the many criticisms that were levelled on him while promoting the PQ’s Charter values.

“I believe that a neutral state is a necessary complement to diversity. I think a neutral state goes with diversity, because a neutral state ensures the respect for everyone, for the diversity of opinions and diversity of religion,” he said.

He argued that some had tried to portray him as a “man closed to difference and diversity,” claims he says are not true.

It'll be a tough road for the former cabinet minister -- recent polls show Pierre Karl Peladeau as the heavy favourite to win the leadership.

Fellow MNA Martine Ouellet is the only other person to officially seek the nomination so far.

The next leader of the PQ will be known on May 15 or May 22 if a second round of voting is necessary.

-- with files from CTV Montreal