A New South Wales woman who blogged about her sick child has sobbed while leaving a court hearing where it was alleged she used urine to poison her child.

Officers from the NSW Child Abuse Squad started investigating in 2014.

The woman, 48, has pleaded not guilty to assault occasioning actual bodily harm and using poison to endanger life.

The woman was investigated after medical staff at Sydney's Westmead Children's Hospital and the John Hunter Children's Hospital raised concerns about fast-growing organisms in her then eight-year-old's urine and blood.

The girl has a genetic illness and was regularly in both hospitals.

Child abuse squad detectives allege on three separate occasions a mixture of yeast and fungus grew in one of the tubes that made up the daughter's venous line, in a way that indicated contamination by urine.

The police brief said medical staff had never witnessed such a scenario before.

The woman is comforted by her husband as she stands accused of poisoning her daughter with urine. ( ABC: Anthony Scully )

Mother denies deliberately making child ill

The prosecution alleges this was a case of Munchausen syndrome by proxy, where a parent makes their child sick.

The mother strenuously rejects that.

Crown Prosecutor Lee Carr told a directions hearing in Newcastle District Court that the medical evidence was complex.

The claim was echoed by the woman's solicitor Mark Ramsland as he left the court.

The brief of evidence for the case is nearly 15,000 pages long and there are more than 10,000 medical documents.

Mr Carr told the court the material was hard to read.

"I certainly concede the medical records are not easy to digest," he said.

At that point, District Court Judge Roy Ellis said a jury panel may need to be larger than normal, given the confronting nature of the case.

"In terms of the number of jurors, that might be a factor in terms of people who would not want to sit on such a thing," Judge Ellis said.

Mr Carr said that it might be a suitable matter for a judge sitting alone.

Girl cannot remember

Judge Ellis asked the defence legal team if the girl would be giving evidence.

The court heard the girl had been interviewed by police from the child abuse squad and a recording of that had been reviewed by the Crown and defence.

The defence stressed that the girl could not remember much, if anything, that may be able to assist with the proceedings.

Judge Ellis confirmed that the woman's District Court trial would last up to a month.

While leaving court the woman nodded when asked if she loved her daughter.

Both she and her husband comforted each other and wept as they left the court precinct.

Her trial is due to start on February 6, 2019.