Warning: graphic content

Shocked witnesses have tried desperately to help a man who staggered into a Sydney petrol station pleading for help after he was severely burned in a factory fire and explosion.

The disoriented man, identified as being 56 years old and from Marayong, remains in a critical but stable condition in hospital, was found wandering around the service station on Sunnyholt Road in Blacktown about 7.15pm on Friday as he waited desperately for help to arrive.

The man was still wearing boots, but most of his clothes appeared to have been burned off. He was in severe pain, calling out for help, with his skin peeling off his body.

In confronting footage recorded at the petrol station, one good Samaritan was shown pouring water on the man as he staggered around the petrol station before paramedics arrived.