Fears held for Australian man critically injured after apartment block bursts into flames

Grave fears are held for an Australian man who was critically injured after an apartment block in Melbourne's suburbs burst into flames.

More than 200 residents of the public housing building in Fitzroy, three kilometers north of Melbourne's CBD, awoke screams and panic on Wednesday morning as the building was engulfed by flames in an incident authorities are treating as suspicious.

Ambulance Victoria said that five people were taken to hospital including one man in a critical condition.

Another of those taken to hospital was a firefighter suffering from smoke inhalation.

"A man has serious burns to the face, arms and back as a result of the fire," Ambulance Victoria Commander Susie Dean told reporters on the scene.

"Paramedics treated his burns and managed his pain and he was taken to The Alfred hospital in a critical condition."

Police confirmed that they believed the fire was started when a mattress in a corridor on the sixth floor of the complex was set on fire, causing thick smoke to spread throughout the building.

The investigation into the incident is ongoing with up to 30 police officers remaining at the scene.

Ranko Cosic, a resident of the building, said he woke up to panic and people screaming.

"I'm on the third level so I went outside to see what was going on, there was a lot of people screaming and yelling," Cosic told News Limited.

"To be honest, it's not that unusual to hear people yell so I just went back inside."

Moments later Cosic said he heard sirens and began to smell smoke.

"I went back to see what was going on and that's when I saw a lot of people panicking," he said.

"I've lived here for 15 years and I've never seen anything like it. People were quite distraught and upset." Endit