A few properties are being evacuated in the North Canterbury township of Pegasus, due to a gas leak.

Fire and Emergency were called to a burst line in Rapaki Street about 12.30pm.

Spokesperson Brent Dunn says there is always a safety risk with gas.

"We have the police responding as well who are helping with cordons."

Police are assisting at the scene and traffic control is also in place, with motorists asked to avoid the area.