The Australian Catholic Social Justice Council has voiced its concern regarding Australia's detention of children and their families.

"It is hard to fathom the Government's expenditure of hundreds of millions of taxpayer dollars on indefinite offshore detention. This 'no advantage' policy is sure to cause harm but it cannot guarantee its policy objective of deterring desperate people.

"We remind all Australians that it is not illegal to seek asylum in Australia.

"We oppose the policy of prolonged detention of asylum seekers but we are particularly concerned about its effects on vulnerable people, especially children.

"We call on the Australian Government to release immediately all children and their families from immigration detention whether that is on the mainland or in these offshore camps", Bishop Saunders concluded.