A plan to have police officers and cadets aboard Winnipeg Transit buses is not sitting well with the city's police union, which says the city cannot use cadets to help patrol buses.

The Winnipeg Police Association says it would be a mistake to include cadets in the transit patrol plan, which is aimed at ensuring the safety of Winnipeg Transit drivers and riders.

Association president Maurice Sabourin says its collective agreement with the police service prevents cadets from being used for "special enforcement projects," which he believes the bus patrols would be.

He added that the agreement prevents cadets from being put at risk of incidents such as the ones that Winnipeg Transit drivers have reported in the past year.

"The Amalgamated Transit Union came forward to the police service because their drivers are being violently attacked," he said Monday.

"Cadets are not as well-equipped as police officers. They only have intermediate weapons which doesn't allow them to deal with, say, a knife attack or a lethal force encounter. So safety is a huge issue because on a moving bus, there's no escape route for them if they get into a situation where they'd have to turn and run."

The Amalgamated Transit Union (ATU) Local 1505, which represents Winnipeg Transit drivers, reported last month that violence against drivers went up by 54 per cent between 2014 and 2015.

Sabourin said he has already voiced his concerns to police Chief Devon Clunis, who will present the patrol plan at a meeting of the Winnipeg Police Board on Friday.

"When this is a special enforcement project, specifically to target the violence that is occurring to the drivers, I think they're making a big mistake by even just trying to allow the cadets to be involved," Sabourin said.

He added that the union was not consulted on the idea of putting officers and cadets on transit buses.