Fewtrell also said the rescue teams were hampered by a series of setbacks as the search continued through the night.
”There’s been a range of complications throughout the operation,” he said.
”The job of rescue (teams) is to work their way through and try and find spaces in that collapse area where someone might have been caught.
”And so part of that work involves this sort of very manual labour of piece by piece, picking up the debris and moving that away.”
Complications included a gas leak, safety concerns about how much work could happen at the site and fire underneath the rubble in the collapsed area. Firefighters have been unable to directly reach the fire because of the debris, according to Fewtrell.
”But we are able to apply water onto that, the water obviously then drains down and suppresses the fire,” he said.
Crews rescued a woman in her 60s and a wheelchair-bound woman in her 70s from the ruins on Saturday afternoon, and later saved a small dog that was in good health.
The women were among five people at the scene taken to hospital - three to Mount Druitt Hospital and two to Hawkesbury District Health Service.
All had been released by Sunday morning as emergency crews continued to search the building for the other person.
The missing person was on the second floor of the building when it collapsed, Fewtrell said.
Emergency services were yet to establish what caused the blast. Firefighters have used seismic monitoring equipment to capture any sounds under the ruins.
NSW Police, who said the incident was under investigation, were initially called to reports of a gas explosion.
Gas mains were isolated at the property earlier on Saturday so crews could safely step up their search and use concrete cutters to remove the debris.
