Brisbane mother accused of trying to kill her baby girl claims she was "possessed".

A Queensland jury is set to hear further evidence from the ex-husband of a woman with “strong Christian values” who is accused of twice trying to murder her infant daughter.

A Brisbane Supreme Court jury on Wednesday heard Ashleigh Meagan Watterson told police “my hands might have done it but my head didn’t do it” in August 2013, more than a year after her 21-month-old daughter Sarah died.

“I never wanted to hurt (Sarah) but at those events, I feel I was possessed,” she said in a signed police statement shown to the Brisbane Supreme Court on Wednesday.

“I believe I have the love of God and this is not the person who I am.

“I feel that the devil attacked and made me do things.”

Sarah died on March 20, 2012, aged 21 months, with the cause undetermined. Watterson has not been charged in relation to her death.

She has pleaded not guilty to two counts of attempted murder and assault occasioning grievous bodily harm over attempts to kill her daughter on October 28 and November 24, 2010.

“She was four and five months old when her 23-year-old mother unsuccessfully tried to murder her on two separate occasions,” Crown prosecutor Daniel Boyle told the jury.

The mum says she was attacked by the devil who "made her do things".

"She did that by the deliberate obstruction to the airways."

Sarah recovered from the first alleged attempt to kill her after being revived by paramedics but suffered "catastrophic consequences", the court heard.

"Unfortunately, the period of lack of blood and oxygen to the brain resulted in severe brain damage," Mr Boyle said.

Watterson said she had left Sarah on the floor of the family home at Rothwell, north of Brisbane, for less than a minute and returned to find her blue and not breathing.

She was in hospital for six days but half an hour after being discharged she was again found blue, unresponsive and not breathing.

"The accused told them she had left for five minutes and returned to find the child not breathing," Mr Boyle said.

Three weeks later, Watterson was alleged to have tried to kill her daughter during a hospital visit where she was due to discuss a non-resuscitation order for Sarah with doctors and nurses, he said.

According to the Crown's case, she took her daughter outside but when they returned to the ward, nurses noticed Sarah was limp and her translucent skin cool to the touch.

In the days following her alleged August 2013 confession, Watterson texted her then-husband she was "not planning to tell anyone that I am guilty".

During the exchange, she wrote that she was still the same person and her mother had taken the alleged confession "kinda better than expected".

Sixteen doctors and four nurses will give evidence during the trial, the jury heard.

Defence barrister Donald MacKenzie told the jury Watterson never harmed Sarah and her confessions "came from a disordered mind".

The trial is expected to run for two weeks before Justice Glenn Martin.

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