The immigration minister, Peter Dutton, said the claims were being investigated but called them “hype” and blamed “left wing” media outlets. He claimed to be aware of some “false allegations of sexual assault, because in the end, people have paid money to people smugglers and they want to come to our country.”

Many Australians were less sanguine as they digested the fact that more than half of the complaints of abuse and mistreatment involved minors. Criticism of these forbidding outposts, known as regional processing centers, has swelled into a chorus of complaint — with a growing sense that this solution of offshore detention has failed to protect basic human rights in both conception and execution.

There can be no denying, though, that along with the policy of turning back any boat arrivals, offshore detention has been an effective deterrent; the number of people arriving by sea has dropped from thousands to almost nothing.

In 2009, 5,609 people traveled to Australia in tiny cramped boats, seeking refuge. By 2012, it had rocketed to 25,173. Kevin Rudd, the prime minister at the time, vowed that no one who tried to get here by sea would ever be allowed to settle. The opposition party successfully ran on a slogan of “Stop the Boats” in the next election, and by 2014-15, the numbers were down to 158. Now it is virtually zero. And the success of this approach has meant the number of people in detention more generally has plummeted: in 2013 there were almost 2,000 children in onshore and offshore detention; now there is little more than a hundred.

And yet the question now is: At what cost has this been achieved?

Abuse accusations aside, the policy is costing Australia billions of dollars. For every detainee housed on the island of Manus, which actually belongs to Papua New Guinea, taxpayers have shelled out more than $1 million since 2011. At the end of June, there were 854 detainees in the men-only facility on Manus. Those on Nauru numbered 442, including 49 children and 55 women.