18/11/2016 1:17 PM AEDT | Updated 19/11/2016 9:57 AM AEDT

Two Still Critical After 'Man Set Fire' To Melbourne Bank

The alleged perpetrator remains under police guard in hospital.

Two people are fighting for life in hospital and 4 others are recovering from serious burns after a man set himself on fire in a crowded Melbourne bank on Friday.

The 21-year-old who allegedly set fire to the bank is said to have entered the Springvale Commonwealth Bank with flammable accelerant used to ignite the fire about 11.30am AEDT.

CCTV footage allegedly shows the man taking a large plastic container and heading towards the bank just before the fire, the Nine Network reports.

The suspect is said to be an asylum seeker from Myanmar on a bridging visa.

As many as 27 people -- including 3 children -- had to be treated for a mixture of burns and smoke inhalation, while the man who allegedly started the fire remains under guard at hospital.

Fairfax/Ernesto Gonzalez
Police speak with a man out the back of the Commonwealth bank branch on Friday

On Friday, Country Fire Authority spokesman Paul Carrigg told reporters he understood there had been an explosion just inside the front entrance of the bank shortly after 11.30. But, he said, firefighters had not seen a container of accelerant.

"We haven't gone in search for it, it is a crime scene," he said.

"There's been apparently a flammable liquid, not sure what it was."

Police said they were unsure at this stage if there was an explosion.

The motive of the alleged attacker is not yet clear.

"We don't know much about him. We haven't had a chance to speak with him. He is injured and he is being attended to at hospital," Inspector Jaqui Poider told reporters.

State Health Commander Paul Holman said 25 ambulance vehicles were sent to the scene.

The bank was evacuated and Springvale Road closed in both directions.