The main burst shortly after 12pm today on the footpath next to the Ray White building in Phillip, on the corner of Townshend Street and Grenville Circuit.

Jason Bishop, owner of Canberra Camping and Kayaks across the road from the burst main, said the water pressure was so high, it had ripped up part of the asphalt footpath.

"It was incredible," he said. "It was maybe four cars high."

Nobody is believed to have been injured.

Mr Bishop said he was unsure how the main burst, as there was no work being done in the area.

He was returning from lunch at about 12pm when he noticed the water jet.

"I just happened to look out the look out the window and saw the water," he said.

At one point a crowd of up to twenty shoppers gathered to watch the spectacle.

Mr Bishop said police and ACTEW Water personnel worked to keep shoppers away from the water and shut down the mains.

Kym Lovett from Ray White Commercial said at this point, there does not appear to be any damage to the real estate agent's offices and no water made it inside.

"It all just came as a complete surprise," he said.

As a precautionary measure, Mr Lovett said he had asked ACTEW Water to send a structural engineer to inspect the property.

Water supply in the area, including to some nearby buildings, was stopped following the incident. An ACTEW Water spokesperson said engineers were working to repair the burst main this afternoon.

"Inspectors shut down the water supply shortly after it was reported in order to reduce the impact on our customers. It has been necessary to install temporary traffic management to carry out this repair as quickly as possible," the spokesperson said in a statement.

"We apologise for any inconvenience this may have caused."

The ACTEW Water website said water supply to the area was expected to be restored shortly after 3pm.