A 30-metre long crack that has developed on Elizabeth Street in the north of Melbourne's CBD is believed to have been caused by excavation at an adjacent construction site.
The crack has caused the closure of Elizabeth Street's northbound lanes between the Haymarket roundabout and Grattan Street. A water main at the site has also sprung a leak, and crews are digging down to try to fix the problem.
A VicRoads spokesman said the crack was detected last night in the roadway adjacent to the Victorian Comprehensive Cancer Centre construction site.
A decision was made this morning to close the busy street.
"Given the nearby construction activity and deep excavation for the Victorian Comprehensive Cancer Centre project, VicRoads is working closely with [construction company] Grocon to identify the cause and is monitoring the site and road area," the spokesman said.
"VicRoads will be performing emergency repair works over the weekend and reopen the road as soon as possible."
City West Water crews are also attempting to fix the leaking water main, however a spokeswoman said customers' water supply was not being affected.
VicRoads advised drivers to avoid the area, particularly during this afternoon's peak. Motorists who do travel through the area should follow detour signs.
"VicRoads apologises for the inconvenience and thanks drivers for their understanding and patience," the spokesman said.
The road closure is not affecting route 19 tram services, which are still running along Royal Parade and Elizabeth Street.
Anyone in the area experiencing problems with their water supply should contact City West Water on 132 642.