She said the government was wrong to argue - as Mr Morrison and Home Affairs Minister Peter Dutton do - that children and families are technically not"in detention"in Nauru.

"Sure - they're not behind bars and they can walk about freely,"she said,but their long and ongoing time in Nauru amounted to"a detention of their mind and their spirit".

Ms Banks said the calculation between offshore processing and keeping the boats stopped had been"overridden"by the plight of sick children and Australia's"humanitarian obligation"to get them off the island.

"What was a defensible argument in the past is weaker now with the current facts,"she said."In the past few months the political games and distractions of both parties have disgracefully played out in this place,and in the meantime the situation in Nauru with sick children has reached a crisis point.

"Children are citizens of the world,and the children on Nauru are our ultimate responsibility. Long term,indefinite detention is no place for any child."

Ms Banks warned the Australian government may have to apologise in coming years to the families it has sent to Nauru,just as Mr Morrison apologised to survivors of child sexual abuse this week.

The number of children on Nauru has reduced dramatically in recent weeks as a result of Federal Court orders to take sick children and their families to Australia. Mr Morrison also said he was"quietly and methodically"getting people off the island rather than"grandstanding"about it.

On Monday night there were 52 children on Nauru,according to the Department of Home Affairs,and more have been taken to Australia since. However,the government says they will not be allowed to resettle here permanently.

Close to 450 refugees have been resettled in the US,but many hundreds more are yet to be accepted,and 188 have been rejected - with no obvious alternatives for resettlement.