Australia has gone to great lengths to prevent outsiders from seeing what goes on in these offshore prisons. The contractors who work there are subject to criminal prosecution for speaking publicly about conditions at the centers. Nauru, which has profited handsomely from the deal, has made efforts to shield the arrangement from scrutiny. In 2014, it raised the cost of a journalist visa from $178 to $7,126 and it barred a team from the United Nations Working Group on Arbitrary Detention from visiting.

Amnesty International found that suicide attempts among refugees and asylum seekers on Nauru have become disturbingly common. In late April, Omid Masoumali, a 23-year-old refugee from Iran, set himself ablaze in Nauru after shouting: “This is how tired we are. … I cannot take it anymore.” The following month, a Somali refugee, Hodan Yasin, set herself on fire. Mr. Masoumali died. Ms. Yasin survived, but suffered burns to 70 percent of her body.

Among the 58 refugees and asylum seekers Amnesty International interviewed, most said they experienced severe emotional distress. One Iranian man, according to the report, said his pregnant wife attempted to hang herself. She told him, “I’m homeless; I can’t bring another person into this world.”

While the number of refugees held on Nauru and Manus Island is small compared with refugee numbers in the Middle East and Europe, Australia’s inhumane imprisonment of desperate people is a disgrace. The government should end its offshore processing of refugees and stop treating anyone who approaches its borders without a visa as automatically inadmissible. The United Nations can assist by redoubling efforts to resettle those stranded on the two islands and by putting pressure on Australia to change its policy.