Fire and Rescue NSW (FRNSW) crews have rushed to the scene of an explosion and building collapse this afternoon at Whalan, in Sydney’s west.

The blast occurred in Waikanda Crescent, just before 1pm today.

FRNSW firefighters and other first responders have rescued two people, a woman in her 60’s and a wheelchair-bound woman, in her 70’s, from the ruins and have commenced a search and rescue operation to determine if others are trapped in the rubble.

The women have been medically assessed and remain in the care of Ambulance paramedics.

The large blast blew out windows and damaged neighbouring townhouses in the multi-apartment complex.

The gas company has been unable to cut off supply to the scene and is attempting to isolate the mains.

There is no fire at present but the scene remains volatile and unstable.

FRNSW has more than a dozen units at the location, including Rescue, HAZMAT and ladder platform appliances.

FRNSW is also using Remotely Piloted Aircraft Systems (RPAS) or drones to make an aerial assessment of the blast zone.

The public is urged to stay away from the scene while emergency operations continue.

FRNSW will issue more public information as it becomes available.