Rescue workers are searching for Bianka O’Brien and her 12-month-old son after fire engulfed a convenience store in Rozelle and adjoining units at 4am on Thursday.
It’s believe Ms O’Brien, 31, and her baby were asleep in a unit upstairs at the rear of the shop.
The woman’s husband was not home when the explosion shook the street.
A 30-year-old man, who lived in another unit, is also missing.
We always hold out hope. It’s not a recovery operation and we’re still hoping to find some survivors.
Emergency services are attempting to shore up the walls of the surrounding buildings and put cameras into voids.
Dogs are being used to try to locate the missing trio who lived in neighbouring apartments.
“It’s still a rescue and horrific as the scene is down there we are still holding out hope that there are some survivors,” NSW Fire and Rescue (NSWFR) Superintendent Paul Johnstone said.
“We always hold out hope. It’s not a recovery operation and we’re still hoping to find some survivors.”
State Emergency Service (SES) volunteers with sniffer dogs have arrived at the scene to help scour the rubble of the burnt out building.
Police Superintendent Clive Ainley said there was a report of a car driving away from the scene when the explosion occurred.
“I don’t know what part that car plays in the investigation at this time,” he said.
Darling St is expected to remain closed off for the rest of Thursday and possibly into Friday morning.
Supt Johnstone said an initial blast about 4am on Thursday had blown out windows up to 100m away.