Southbound lanes of the Diefenbaker Bridge in Prince Albert are closed after officials noticed a crack in one of the girders.
The bridge is the only way across the river in the city.
City manager Robert Cotterill said officials closed the lanes because of safety concerns.
"When you look at this picture, and you see a complete crack in the girder, you know you've got a serious metal fatigue problem," Cotterill said.
It was not known what caused the crack and CBC News was told it could be months before the lanes are open again to traffic.
Cotterill said motorists can expect delays making their way across the bridge.
"We have over 140 thousand people come to and from P.A. on a weekly basis," he said. "So for us this is a huge problem. And it's a provincial problem because we're down to two lanes when we normally have four."