A BURST water main is causing traffic chaos in the Brisbane CBD as pedestrians and motorists contend with water coming from both above and below.

The main burst at the intersection of Margaret St and George St just after 5am. But while the flow has been stemmed the damage caused by shooting water has forced the closure of one lane on Margaret St and the footpath.

Brisbane Central District Duty Officer Sen-Sgt Alan Minto said the burst main sent pavers flying and left a big hole on the footpath that had since been cordoned off by police and Brisbane City Council crews. "The burst water main created a big hole on the footpath because it blew off all the pavers," he said.

"It’s causing a bit of traffic congestion as traffic converging off the Captain Cook Bridge off-ramp and off the Riverside Expressway all heads into the city through that area. When you close one lane it creates a few problems."

Earlier, water from the burst main had been reported as flowing as far as Queens Wharf Rd, near the Pacific Motorway. Police are at the scene helping to direct traffic through the area.

Queensland Urban Utilities repair crews have arrived at the scene to help repair the burst main. A spokeswoman said water supply in the immediate area had been affected. "At this stage it is not known when supply is expected to be restored," she said.

"The cause of the burst is not known."

She said crews were working to repair the burst main and restore water to the area as quickly as possible.