The cost of stopping the boats has been calculated at more than $9.6 billion since 2013, and will be another $5.7 billion over the next four years, according to a study by Save the Children and UNICEF.

The study estimates the cost of keeping around 2000 asylum seekers and refugees on Manus Island and Nauru at $400,000 per person, compared with just $33,000 for those on bridging visas in the Australian community.

It asserts the policy is inflicting incalculable harm on asylum seekers, especially children; straining bilateral relationships; and damaging Australia's bid for a seat on the United Nation's Human Rights Council.

It calls on the Turnbull Government to commit to a timeline for resettling those on Nauru and Manus Island, legislate against the detention of children and revoke the ban on resettling refugees who arrived in Indonesia after July 1 2014.