Neighbours reported smelling gas for up to three weeks before police closed roads and shut the tube station in Notting Hill Gate on Tuesday.
National Grid workmen began to dig down to the gas pipes, watched by fire fighters who arrived at 10.45pm to oversee the operation and stayed at the site until 4am yesterday morning..
"We smelt gas about three weeks ago. If that would have blown - boom," said an employee of James Knight Fishmongers, across the road from the repair site.
Roads - including Pembridge Road, Ladbroke Road, Notting Hill Gate and Campden Hill Road - were closed to traffic and trains were not allowed to stop at Notting Hill tube station.
"It is dangerous. The smell gives you a headache. Everyone is complaining. It is not the first time they have dug the road, they did it about three to four months ago," said florist Peter Lyons, who was forced to move his stall further up the street while the work continued.
Ylenia Trupia, 33, who is employed in Notting Hill Gate, added: " Everything is a bit chaotic and a bit confusing."
The Gate pub was forced to close all of Tuesday evening and had some of their stock temporarily removed from their cellar. The roads were reopened on yesterday but a large hole surrounded by wire fencing remains. National Grid is working to complete the repairs as soon as possible.