The man who led a review of abuse allegations inside the defence force has raised doubts about the fitness to lead of every male who graduated as an officer between 1986 and 1998.

The force likely contains a significant number of middle or senior-ranked officers who raped fellow female cadets and could be bound for even more senior ranks, Gary Rumble has told a Senate inquiry.

That’s because Defence failed to take effective action over allegations of abuse at the Australian Defence Force Academy.

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Dr Rumble, who led what’s known as the DLA Piper review, said the only way to get to the bottom of the allegations is with a royal commission.

His review revealed myriad incidents of sexual and other abuse dating back decades.

Dr Rumble said there was a history of sexual assault and defence mismanagement from the time ADFA opened in Canberra in 1986, peaking in the 1990s and diminishing but not disappearing entirely following reforms in 1998.

There was a very high risk officers in middle and senior management positions with potential to rise further, who were cadets at ADFA, raped or committed other serious sexual assaults on other cadets or did not intervene, he told a hearing of the inquiry in Canberra on Wednesday.

Dr Rumble said it was likely there were many more perpetrators than the so-called ADFA 24.

That case relates to 15 cases of rape and nine of sexual assault allegedly committed by male ADFA cadets against female cadets between 1994 and 1998.

They were never properly investigated at the time.

The royal commission into institutional responses to child sexual abuse was a model of how the allegations could be investigated, Dr Rumble said.

Defence Minister David Johnston said the Defence Abuse Response Taskforce was now reviewing calls for a royal commission.

It also was seeking to provide restorative justice to victims on the basis that they had been treated badly.

Senator Johnston said there appeared to be an “understandable” reluctance by many victims to suffer the trauma of telling their story to a royal commission.

They likely would have to revisit events “blow by blow, event by event and all of the terrible things that have happened to them’.

“It’s clear that they don’t want that.”

However, Senator Johnston left the door open for a royal commission if there were a number of complainants making that demand.