A 25-year-old refrigeration mechanic was killed when his van exploded Monday morning in front of his home in the Melbourne suburb of Mulgrave.

The victim, whose name was withheld, died while being treated at the Alfred Hospital from severe internal injuries and deep lacerations in the body and head caused by the powerful 6:50 a.m. blast at the Stadium Circuit.

The blast was caused by the ignition of a leaking gas cylinder located at the back of the van, according to emergency workers in the scene.

A fire and emergency services spokesman said the oxy-acetylene, a highly flammable gas, is commonly used by plumbers and refrigeration mechanics.

The force of the blast broke windows of nearby houses and threw debris up to 300 meters away from the van. It also reduced the van into a smoldering wreck.

A witness said she saw the man flung five metres to the wall of his home by the explosion.

Up to 20 homes, including that of the victim's, were damaged in the explosion.

"When the vehicle has exploded, debris has been thrown probably about 300 metres away from the site of the explosion and ... debris appears to have gone through people's front windows or pierced their roofing," Metropolitan Fire Brigade Commander Andrew O'Connell said, according to Otago Daily Times.

No one else was injured but the dead victim's were treated for emotional distress at the scene.