Tas woman with serious burns critical

A young Tasmanian woman is fighting for life in a Melbourne hospital after she suffered burns to her face and body in a suspected assault by her boyfriend.

The 20-year-old woman's burns were so serious she was flown to the specialist burns unit at The Alfred hospital late on Monday night after the incident in Hobart.

A 34-year-old man was arrested for assault and is currently in police custody.

Detective Inspector Craig Joel told AAP an accelerant of some type, such as petrol, had been used during the attack, which occurred in a corrugated iron backyard shed at a Chigwell home.

Detectives, forensic police, forensic scientists and Tasmania Fire Service scene examiners remained at the Corranga Drive address throughout Tuesday.

The results of chemical testing are not yet known.

Det Insp Joel says family, friends and neighbours have been coming forward during the day to give witness statements.

"There is a history of family violence between the man and woman, and this will form part of the police investigation," he said in a statement.

He described the woman's condition as "grave".

The Alfred hospital said the woman remains in a critical condition.

The man also suffered burns to his body and is being treated in the Royal Hobart hospital under police guard.

National domestic violence helpline: 1800 737 732 or 1800RESPECT. In an emergency call triple-zero.