Central Scotland Police cordoned off streets leading to the city centre, and evacuated homes, shops and other businesses in the area. Shoppers heading in to the area were turned back.
NHS incident response vehicles were also present on standby.
Stirling Council set up a shelter at the Cowane Centre, where they offered chilly evacuees teas and coffees, while investigations continued into the cause of the leak.
Gas workers focused in an area near the junction between Barnton Street, Maxwell Place and Murray Place, close to the busy Stirling Arcade and Thistle indoor shopping centres.
Central Scotland Police, who had more than a dozen vehicles on the scene, said they had been alerted by members of the public at around 11:30am yesterday.