Winnipeg's transit union says service disruptions caused by the current labour dispute with the City of Winnipeg could linger well into the future.

Up to 31 routes could see late or cancelled buses starting Tuesday because drivers have been refusing voluntary overtime for a few weeks.

But Amalgamated Transit Union President John Callahan said the overtime ban also includes bus mechanics.

He said that's created a backlog of buses that need to be fixed and could cause service disruptions for six months to a year, even if the overtime provision was lifted right away.

A number of buses are sitting idle in the Fort Rouge transit yard along the northern part of the property.

Starting Tuesday, May 19, delays and cancellations could hit 18 morning rush hour routes, including routes: 18, 22, 25, 30, 31, 34, 40, 41, 44, 46, 57, 58, 59, 68, 162, 163, 181 and 183.

Thirteen afternoon rush hour commutes could be affected, including routes: 11, 16, 18, 25, 29, 38, 41, 48, 54, 58, 162, 163 and 183.

The union said it plans to meet with city officials and a mediator Tuesday in an attempt to break the impasse.