Orange Fire and Rescue station officer Andrew Webb said a fire crew arrived at 11.07am.

"We secured the scene and evacuated local residents and businesses with police," he said.

Station Officer Webb said people within "100-200 metres" of the roadworks to install a roundabout at the intersection of McLachlan and March streets were evacuated.

"The wind was blowing to the north-east, they were the main people who were evacuated," he said.

Station Officer Webb said a crew from Jemena Gas repaired the pipe.

He said council workers also assisted at the scene.

Station Officer Webb said the work was completed by 11.45am when the fire crew left the scene.

An Orange City Council spokesman said council water crews excavating as part of preparations to build the new roundabout ruptured an "undocumented" gas line.

"During the design phase, there were two separate checks of all underground services and this undocumented 30 millimetre gas line did not appear on any of the maps," he said.

"Usually PVC pipes like this one are also installed with a tracer wire which lets them be detected from above. There was no tracer wire with this pipe. It was not possible to detect it."