A man has been seriously injured in an apartment explosion in Sydney’s west.

The explosion at a residence on Clarence St, Lidcombe sent debris flying just after 6.30am on Friday.

WATCH THE VIDEO ABOVE: Apartment block explodes in Western Sydney

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It triggered a major emergency response, with multiple agencies descending on the building and working to free anyone trapped inside.

One man, believed to be aged in his 40s, was pulled unconscious from rubble and taken to Westmead hospital with serious injuries.

The man is now awake and is speaking with police.

Another person was taken to hospital for smoke inhalation.

The remaining residents have been accounted for.

As a precaution fire crews evacuated 40 residents from three adjoining unit blocks.

Fire Rescue NSW superintendent Adam Dewberry said despite suffering significant damage, the building appears to be stable.

“We are monitoring the building with lasers to check to see if there is any further movement,” he said.

“The recovery operation has commenced.”

He said a wall had “blown out” and caused damage to a car underneath it.

A number of residents will be displaced and won’t be able to go home.

Emergency services are organising the retrieval of essential supplies from inside for the evacuated residents.

Investigations into the cause of the explosion are ongoing.