The audit by leading safety expert David Caple uncovered significant under-reporting of violence in schools, often due to the sheer frequency of incidents and the complexity of logging them via the standard ACT public service "Riskman" safety portal.

While the review found the rate of violence reported by Canberra teachers had remained steady for the past decade, at between 400 and 600 incidents logged each year, consultation with schools revealed they were just the tip of the iceberg.

Those cases which made it "above the waterline" were usually the more extreme as many more went undisclosed, the report warned.

The April 2017 review, which was only recently made public, levelled some of the blame at Riskman, a portal schools called overly complex, difficult to access and more appropriate to an industrial setting.

"Principals and staff described Riskman as a 'black hole' where data is entered but no feedback is provided," the report said.

The ACT education directorate has stressed the importance of a central reporting tool to track incidents, but Professor Caple said that, though commonly used for safety, Riskman was not appropriate for recording the psychological and physical injuries caused by violence and an alternative was needed.

In response to the Caple review, internal audits and a WorkSafe ACT investigation, the directorate has acknowledged the problem of under-reporting and overhauled its occupational violence policies, unveiling a new management plan in July 2017. Touted as the first of its kind in Australia and developed alongside the union, it addresses a number of the Caple report's other recommendations such as increased staff training.

But the directorate defended Riskman this week as important for the consistency of incident data across the ACT public service.

"An independent audit of the ACT’s work health and safety systems recently found Riskman to be appropriate and fit for purpose," a spokesman said.

The directorate did not provide a copy of that audit on request but said it had since created a separate work health and safety hotline for staff. Riskman is regularly updated based off user feedback and the government is currently piloting a new mobile version, the spokesman said.

But, while the directorate has also beefed up its work, health and safety team, it confirmed it has not conducted an audit into staffing levels in classrooms, as recommended by the Caple review.

Professor Caple, who also called for a hard look at the ratio of teachers to learning support assistants, said there was no magic number for safe staffing but such decisions needed to begin from a risk perspective.

"This [review] left me with so much admiration for the teachers and the LSAs," Professor Caple said.

Some schools he interviewed spoke of burn-out and the toll of sustained violence, which most commonly happened in the younger year levels and often involved students with complex needs related to disability or trauma.

Learning assistants lodged about twice as many reports of violence as teachers, yet said they actually recorded very few compared to what they experienced day-to-day. One assistant said she was "in the firing line" for students with patterns of behaviour involving biting, hitting, kicking or throwing objects.

"Very few incidents are recorded in Riskman...often due to the frequency of the incidents and the difficulty of accessing computers and finding the time to complete the necessary documentation," the Caple report said.

As well as calling for more psychological support for educators, Professor Caple recommended rotating staff in specialist settings through different duties to avoid prolonged exposure to violence, an option the directorate said had already been available to schools for some time but was "made explicit" in the wake of his review.

Some educators also called for more accountability around resourcing, saying the system for assigning learning assistants was opaque and not flexible enough for children impacted by trauma.

The directorate spokesman said schools are funded and staffed to meet the needs of all students.

While the union is pushing for maximum class sizes to be enshrined in workplace agreements, it said extra staff were often deployed by the directorate to schools on a case by case basis in response to risks.

The Caple review also praised a trial "positive behaviour learning model" that appeared to be reducing risk on the ground in Canberra schools by recording good behaviour into apps and offering feedback and rewards.

The directorate confirmed that program had since been expanded from about 20 schools to 51 and there were plans to roll it out to all public schools.

A support team deploying experts such as psychologists, safety advisors and speech pathologists to schools as needed was also welcomed by teachers, Professor Caple said, though many noted there was a "lack of time available [for the] specialists to spend with the school".

The directorate has attributed a sharp spike in reports of violence in schools this past financial year to an improved reporting culture.

But a number of educators have since come forward claiming they were actively discouraged by school leaders from reporting violence in their classrooms as recently as this year.

The directorate, which has committed to making schools safer, said it would seek feedback from staff on potential disincentives to reporting in the first half of next year.

Education Minister Yvette Berry has acknowledged the problem will not be solved overnight and will require significant cultural change in schools.

It was crucial to balance the right of every child to an inclusive education with the need to keep schools safe, she said.