The union representing Canada Post carriers is speaking out against a possible move to mail Publisacs in certain parts of Montreal, skirting a city bylaw which requires residents opt-in to receive them.

It’s the latest chapter in an ongoing spat involving the City of Montreal, Publisac's publisher, and Canada Post.

As of Monday, a new pilot project will see people in Snowdon and the Chabanel neighbourhoods receive a revamped, paper-only Publisac in the mail.

“The weight of the day-to-day work of the letter carrier … it’s not made to handle such a weight and such a volume,” said union spokesperson Yannick Scott.

He says mailbags can only hold 70 of those new flyers, meaning they’ll have to return to their trucks more often to grab other mail. And, he adds, heavier bags and Montreal winters don't mix.

“That could bring a health and safety issue,” said Scott.

The new version is intended to replace the old Publisac, which will stop being delivered in Montreal as of next May.

“I do agree with the union, and I’m behind their position on this for sure,” said Montreal Mayor Valerie Plante on Thursday.

Plante has long spoken out against Publisac’s business model, saying the packages produce significant waste.

In an effort to reduce the amount of unused Publisacs ending up in the bin, the city passed a bylaw in April, requiring that the bags only be distributed to people who opt in.

It was first reported by the Journal de Montreal that Publisac’s distributor, TC Transcontinental, intended to use Canada Post to skirt that guideline. The company refused to comment.

“We have to fight to make (sure a) bylaw is being respected," said the mayor. “This is where I’m really upset. I think it’s not respectful for the municipalities’ autonomy, and that [Canada Post] doesn’t seem to care about our bylaws.”

Canada Post said that its employees are obligated to deliver all mail, including marketing mail that is properly prepared and paid for.

"We also have standards in place to ensure we do so in a safe manner," CP said. "It is our long-standing mandated responsibility, which means we are not in a position to pick and choose what mail is delivered. If any customers wish to opt-out from receiving Neighbourhood Mail, they can do so through our Consumer’s Choice program and we will respect that choice. Some items, such as government and political mailings and community newspapers, are exempted."