An electrical cable has exploded beneath a footpath on a busy Bondi street, forcing the evacuation of a nearby charity shop.
The explosion occurred at the corner of Hall Street and Chambers Avenue about 10.30am on Monday.
A Fire and Rescue NSW spokesman said there appeared to be a fault where two underground cables had been joined together.
"When they join the cables up they put a rubber boot around them and fill it up with tar," the spokesman said.
"There's obviously a fault there somewhere and it has vibrated, created heat, boiled the tar and exploded.
"There's no fire, smoke just comes out."
No one was injured in the explosion, however three people have been evacuated from a nearby Vinnies Retail Centre charity store as a precaution.
An Ausgrid spokesman said crews were at the scene working in the low-voltage cable pit.
There were no reports of power outages in the area, he said.