A Queensland girl killed by her mother became ‘invisible’ in the system due failings by child protection agencies, a coroner has ruled.

Neither Queensland’s department of child safety nor a private agency did enough to protect a girl bashed to death by her mother, a coroner has ruled.

The eight-year-old was found dead at her Cairns home after being repeatedly struck with a vacuum cleaner pole in November 2011.

The mother is serving seven years’ jail after last year pleading guilty to manslaughter.

An inquest examining the involvement of government departments, private agencies and the girl’s extended family was held this month in Cairns.

“(The girl’s) death was caused by her mother, however, there are number of factors which significantly impacted upon this outcome,” Northern Coroner Jane Bentley said in her findings, handed down on Friday.

She said decisions made by staff from the department involved in the case were “incorrect, premature and the result of inadequate investigation and assessment”.

The inquest heard the girl became “invisible” in the system and it went undetected that she didn’t attend school for a year before her death, despite her stepfather receiving Centrelink payments.

Child safety put her in foster care in 2010 following abuse claims but she was returned to her mother nine days later.

The decision was made without interviewing the mother or extended family and the school, which the department relied on to monitor the child, wasn’t made aware the girl had been returned to her mother.

Ms Bentley said the inadequacies were the result of understaffing at the office and not the fault of the officer in charge of the case.

Had she had more time to assess the case, she said, she may not have returned the girl to her mother.

She also criticised private abuse prevention agency Act for Kids who were contracted by child safety to engage with the mother.

“The service offered to the girl’s mother was … not of any assistance to the family in any way,” she said.

Moreover, this was concerning as more families would likely be referred to external agencies as a result of the state’s Child Protection Commission of Inquiry.

She said there was a “concerning” lack of information sharing and “misunderstandings” between child safety and Act for Kids.

Three reviews and an Ethical Standards enquiry were held as a result of the girl’s death which resulted in systems and procedures at child safety being addressed.

However, some issues still haven’t been resolved, Ms Bentley said.

It was “inexplicable” that the girl’s extended family, including her aunt, uncle and step grandparents, knew about the abuse but didn’t tell authorities.

A number of recommendations were made, including that an information sharing database between departments and agencies be set up.

Child Safety Minister Tracy Davis said she couldn’t comment on the case, but said the government has been working to reform the child protection system.

This includes setting up the Child Protection Commission of Inquiry with a focus early intervention for vulnerable families.

An Act for Kids spokeswoman said the organisation was unable to provide a comment to AAP on Friday afternoon.