The Koroit/Kepler streets roundabout will be partly closed with a U-turn near the Capitol Cinema as work ramps up on the upgrade as part of the city centre renewal project.
A letter to traders from the council says the street changes will occur from Monday.
"From July 15 the renovation of the Kepler/Koroit intersection will progress to a southern road closure to accommodate upgrades of Wannon Water assets, construction of the new roundabout islands, pedestrian crossings and construction of the new road pavement," the letter says. "Temporary traffic signals will transform the roundabout into a T-intersection, with a U-turn set up on Kepler Street in front of the cinema, accessed via Timor Street."
The letter said works at the Kepler/Timor street intersection was progressing with the majority complete, with remaining works contained to the footpaths and adjacent car parks.
"Council appreciates the community's patience and asks that motorists please observe the temporary traffic signals," it says.