The $40 million refugee resettlement deal with Cambodia is a long-term arrangement that will start small but build over time, Immigration Minister Scott Morrison says.

The deal, announced on Friday and many months in the making, has been condemned by the United Nations’ refugee agency and human rights advocates.

Speaking to the ABC’s AM program, Mr Morrison said four or five refugees will be resettled in the early stages, but only time will tell how many refugees will make the move.

He said it was a long-term agreement and Cambodia would determine how many refugees it would accept.

“You have to start off small, make sure the program is working and then build it up over time,” he said.

“We’re not rushing this – it’s important we get the arrangements right. There are many challenges in running a resettlement program here, we know that.”

Mr Morrison said refugees who chose to go to Cambodia would be housed in the general community and would receive language training before they left Nauru.

Overnight, Amnesty International called the deal “a new low in Australia’s deplorable and inhumane treatment of asylum seekers”.

“In January the Australian Government condemned Cambodia’s human rights record at a UN human rights hearing, but will now relocate vulnerable refugees, possibly including children, to the country,” spokesman Rupert Abbott said.

The United Nations High Commission for Refugees (UNHCR) said it was “deeply concerned” by the precedent the deal sets.

“This is a worrying departure from international norms,” commissioner Antonio Guterres said.

15yo asylum seeker on Nauru attempts suicide: advocate group

Meanwhile, the Refugee Action Collective says a 15-year-old female asylum seeker attempted suicide on Nauru after learning she could be resettled in Cambodia.

The Federal Government has confirmed a 15-year-old girl has been transferred from Nauru to Australia for medical treatment.

The collective’s spokesman Mark Gillespie said the girl’s action was in direct response to the announcement.

“She attempted suicide immediately after watching Scott Morrison’s video saying that the deal that he’s done with Clive Palmer does not apply to the people on Nauru, that they will continue to stay there in limbo or get forced to go to Cambodia,” Mr Gillespie said.