Drivers in the downtown will have to avoid Dundas Street for the next two weeks.
Starting Monday, Dundas between Maitland and William streets will be closed for the installation of new sanitary and water infrastructure beneath the street.
The closure will be in place until December 16.
Detours are in place for drivers and cyclists, city officials said.
Vehicles heading west will be rerouted onto Queens Avenue at William Street, returning to Dundas at Maitland. Eastbound traffic will be detoured at Maitland to Dufferin Avenue, returning to Dundas at William. Meanwhile, cyclists traveling west are advised to peddle around the closure by taking William to Queens and then back to Dundas at Maitland. Cyclists going east can take Maitland to Dufferin, returning to Dundas at William.
London Transit will also be detouring its buses around the closure.
Signage has been erected to help navigate pedestrians around the area.
All businesses will remain open and accessible while crews complete the road work, city officials reassured.