A care worker who was looking after a teenager with severe disabilities when she swallowed a latex glove and choked to death has told a coronial inquest the girl was left unrestrained without supervision for at least two minutes.

Key points: Sophia Nisco's death at a respite facility in February 2017 is being investigated by the coroner

Sophia Nisco's death at a respite facility in February 2017 is being investigated by the coroner Her mother told the inquest she had warned staff about the need for constant supervision

Her mother told the inquest she had warned staff about the need for constant supervision Care worker Sandeep Mangat rejected the mother's statement

Sandeep Mangat was one of two care workers looking after 16-year-old Sophia Nisco when she was found unresponsive in a bathroom at a Felixstow respite facility in Adelaide's east in February 2017.

The court heard Sophia suffered from cerebral palsy, autism, ADHD, hearing and visual impairments and had the mental age of a one-year-old.

Sophia's mother Nella Nisco previously told the South Australian Coroner's Court she had made it clear to staff at the DisAbility Living Inc facility that Sophia could not be left on her own outside her wheelchair.

She said without physical restraint her daughter was very fast and liked to explore the world around her by putting things in her mouth.

But Ms Mangat disputed that, saying she had never been told Sophia needed constant supervision while she was outside her wheelchair.

"[Ms Nisco] didn't say anything like that," she told the court.

Ms Mangat did admit that she had read in the teenager's care plan that Sophia liked putting small toys and objects in her mouth.

The court heard on the afternoon of Sophia's death, she and another carer, Charanjit Singh, were left in charge of four disabled children, including one who required one-on-one attention.

While she and Mr Singh were attending to another child, Sophia was left unattended in a playroom for "probably two minutes", Ms Mangat said.

Once Ms Mangat realised Sophia was missing, she and Mr Singh searched the facility for Sophia, until she was found in the bathroom, the court heard.

Ms Mangat said she could not recall whether she or Mr Singh gave Sophia mouth-to-mouth breaths once they commenced resuscitation.

She also said she did not know whether a box of latex gloves — which were shown on a bathroom vanity in photos tendered to the court — were there on the day Sophia died.

Ms Mangat agreed, when deputy state coroner Anthony Schapel put it to her, that the care load of four high-need children between two carers was "a very heavy burden".

Mother says staff were told about risk

The court had previously seen notes from a staff meeting where Ms Nisco said she raised the need to supervise Sophia when she was out of her wheelchair restraint in the month before her daughter's death.

"Sophia has a fascination with gloves and balloons, and she would try and take gloves off carers," Ms Nisco told the court.

"At home there were many incidences, and at school.

"Staff knew that she was fast, and they knew she was at-risk."

She said she believed funding for extra care hours at the facility was for one-on-one time, despite that not being spelled out in care plan documents provided to the court.

Nella Nisco with daughter Isabella outside the Coroner's Court. ( ABC News: Gabriella Marchant )

Counsel assisting the coroner Kathryn Waite said a witness who worked at the centre corroborated to police that staff knew Sophia was not to be left unattended when she was not in her wheelchair.

Ms Nisco said there had been other issues with care at the respite facility, including a lack of shower chairs at the facility.

"I was shocked … I thought she was being showered in a shower chair, not on the floor," she said.

"Sophia no longer has a voice, I am her voice. I'm hoping for justice and I hope this never happens to a parent with a vulnerable child.

"The [royal commission into disability services] can't come fast enough."

Ms Waite questioned whether the facility had received extra NDIS funding, which Ms Nisco said she believed had begun in the month before her death.

Ms Waite said it would be up to the inquest to decide whether the facility had received adequate funding for the needs of those in its care.

Sophia attended the facility most fortnights to give her family a break from her high-care needs.

The inquest continues.