The man, 23, was seen running from his Green Street unit with smoke coming from his body seconds after a gas explosion in the kitchen about 11.05am.

He ran about 100m to the Wang­aratta hospital, on the corner of Green and Docker streets, where he collapsed onto the lawn.

Bystanders tended to him until hospital staff arrived.

The intern suffered burns to his face and chest and was put into an induced coma and sedated with a breathing tube.

He was flown to The Alfred hospital in Melbourne in the early afternoon where last night he was in a serious but stable condition.

Hospital chief executive Ken Taylor said the man had arrived on a work rotation from Royal Melbourne Hospital two weeks ago.

“Obviously the staff are very distressed,” he said.

“A lot of them were involved in finding him and treating him in emergency.

“He was stable when he went to Melbourne and now we’re just waiting for some good news.”

Witness Shane Jones said the blast “went off like a bomb”.

It left the unit burnt out and structurally damaged, and cracked every window in the block.

It was heard at least 500m away at the Wangaratta police station.

Sgt Brian McCormick said the blast did not appear to be suspicious.

He said no one else was injured in the blast and that the other units appeared to be empty at the time.

“It seems everyone was at work,” he said.

Sgt McCormick said the force of the blast had thrown debris onto the street.

“The unit is totally gutted. It was lucky that no one was walking past at the time,” he said.

The unit is part of a block owned by the hospital and houses interns during their usual 10-week work rotations.

Police cordoned off Green Street between Docker Street and the Wangaratta-Yarrawonga road until mid-afternoon while Country Fire Authority investigators examined the scene.

Wangaratta Council workers cleaned the street and footpaths of debris.

CFA Region 23 operations manager Stewart Kreltszheim said the blast had ignited a fire which had been brought under control by Wangaratta brigades within 20 minutes.

WorkSafe Victoria and Energy Safe Victoria were also investigating the incident.