A man remains in critical condition after suffering severe burns during a procedure at St John of God Hospital in Subiaco. 

It' s understood the man was undergoing a routine procedure for a skin condition, when a fire broke out in the operating theatre.

Nine News Reporter Michael Genovese told Gary Adshead an investigation is now underway.

"Somehow a fire was ignited in the room, and what caused that is subject of a full investigation," Mr Genovese said on 6PR Mornings.

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