A woman who was suffering from severe depression when she killed her husband by setting fire to his house has been jailed for nine years.

A Japanese woman has been sentenced to nine years’ prison for starting a fire that killed her estranged husband and gutted his Brisbane townhouse.

Sakura Suda, 45, quietly sobbed as the sentence was read out in the Supreme Court in Brisbane on Tuesday.

The Japanese national had pleaded guilty to arson and the manslaughter of her husband Kenji Suda.

She poured petrol over Mr Suda before setting his home on fire at Runcorn, in Brisbane’s south, on December 27 2011.

Suda was originally charged with the ferry skipper’s murder, however the charge was downgraded to manslaughter in the Mental Health Court.

She was suffering from significant depression when she started the fire, the Supreme Court heard.

Ms Suda’s marriage had broken down and she feared she’d be denied custody to their nine-year-old daughter.

In the months leading up to the blaze, Mr Suda became increasingly worried about his separated wife’s mental state and let her move into his Runcorn home.

On Christmas Day Suda filled two jerry cans with petrol and hid them in the bedroom of the home.

She bought matches on Boxing Day.

The following night, neighbours heard screaming coming from the burning home.

Suda escaped by jumping from an upstairs window. She fractured her wrist and suffered burns to 17 per cent of her body.

The inferno completely destroyed Mr Suda’s townhouse and badly damaged the unit next door.

In sentencing Suda, Justice David Jackson took her injuries and mental state and into account.

He also said it was difficult to accept Suda planned to kill her husband on the evening in question given she’d told a friend she was going to a party the following day.

“These offences were out of character for you, they stemmed from your mental illness,” Justice Jackson said.

“They also stemmed from your inability to cope with the breakdown of the only family you had, that included the threat of losing contact with your daughter.”

Suda’s daughter, now 11, lives in Japan with her 81-year-old paternal grandmother.

In a sentencing submission, Crown prosecutor Brendan Campbell read out a victim’s impact statement, which outlined the girl’s fears of her mother returning to Japan.

But defence barrister John Allen said Suda would be unlikely to reoffend, and Justice Jackson agreed.

Suda was sentenced to nine years’ imprisonment, but has already served two years and two months in pre-sentence custody.

A parole date for her release hasn’t been set.