Public health professionals have a responsibility to protect and promote the right to health amongst populations, especially vulnerable and disenfranchised groups, such as people seeking asylum and whose health care is frequently compromised. As at 31 March 2016, there was a total of 3707 people (including 384 children) in immigration detention facilities or community detention in Australia, with 431 of them detained for more than 2 years. The Public Health Association of Australia and the Australian Medical Association assert that people seeking asylum in Australia have a right to health in the same way as Australian citizens, and they denounce detention of such people in government facilities for prolonged and indeterminate periods of time. The position of these two professional organisations is consistent with the compelling body of evidence demonstrating the negative impact detention has on health. Yet in recent years, both the Labour and Liberal parties—when at the helm of Australia’s Federal Government—have implemented a suite of regressive policies toward individuals seeking asylum. This has involved enforced legal restrictions on dissenting voices of those working with these populations, including health professionals. This paper outlines Australia’s contemporary offshore immigration detention policy and practices. It summarises evidence on asylum seeker health in detention centres and describes the government’s practice of purposeful silencing of health professionals. The authors examine how Australia’s treatment of asylum seekers violates their health rights. Based on these analyses, the authors call for concrete action to translate the overwhelming body of evidence on the deleterious impacts of immigration detention into ethical policy and pragmatic interventions. To this end, they provide four recommendations for action.