The child safety officers who failed slain toddler Mason Jet Lee suffered "manifestly inadequate" consequences and should have been fired, Queensland's public service watchdog says.
Mason died after his mother's boyfriend struck him so hard in the abdomen it ruptured the 22-month-old's small intestine, leading to an infection.
The blow was one of many serious and painful injuries Mason suffered in the months before his death in June 2016.
Mason's declining health in his final days was largely ignored by his mother, Anne-Maree Lee, and her boyfriend, William O'Sullivan, who are both serving jail sentences for his manslaughter.
The family had been known to the child safety department since before Mason's birth in 2014, but in the months before Mason died, child safety officers saw him only once for about five minutes.
The ethical standards unit later determined that 21 department employees did not carry out their duties appropriately.
After an inquest into his death, deputy state coroner Jane Bentley says the child safety department's handling of Mason's case was "a failure in nearly every possible way".
Premier Annastacia Palaszczuk in 2020 asked the Public Service Commissioner to review the coroner's report.
Released on Friday, the report found that no one staff member was solely responsible for failing to protect Mason, but collectively their lack of action had "dire consequences".
"The disciplinary action that was taken against frontline officers is manifestly inadequate given the objective seriousness and extent of the officers' failings," PCS chief executive Robert Setter said.
"In the most significant cases, some employees should have had their employment terminated."
"We would have expected that some other officers would have received a reduction in pay, and others demoted."
Five frontline officers received a verbal reprimand and three others quit before action could be taken against them.
"It is not possible to understand the rationale of the departmental decision makers that supported such lenient disciplinary action being imposed," Mr Setter added.
Despite finding punishments were inadequate, no further action can legally be taken against staff who have already been disciplined.
Only one person was not disciplined and Mr Setter recommended he be permitted to start disciplinary proceedings against that person, a manager.
Mr Setter also recommended a new investigation be launched into more senior officers for their role in the management of resourcing and workloads, and that any disciplinary action taken by the department against public servants in the next two years be subject to legal advice from Crown Law.
Minister for Children Leanne Linard said the department had not met Mason's needs and for that the government was deeply sorry.
"Across Queensland, our communities and our frontline child safety officers have been profoundly affected by his death," she said in a statement.
Significant changes have been made to strengthen the child protection system, she said, but more would be done to ensure the protection of the state's most vulnerable children.
Australian Associated Press