A U.S. agreement to resettle an unspecified number of refugees would be a "great achievement" if it emptied Australia-run Pacific island camps where asylum seekers were mistreated, a United Nations expert on migrants' rights said Friday.

U.N. Special Rapporteur on the Human Rights of Migrants Francois Crepeau described the bilateral deal announced last weekend as a "good start" to finding a solution that should involve closing asylum seeker camps on the island nations of Nauru and Papua New Guinea.

The United States has agreed to resettle refugees from among 1,300 asylum seekers held on Nauru and on Papua New Guinea's Manus Island for up to four years. Another 370 who came to Australia for medical treatment then refused to return to the islands would also be eligible.

It is not clear if the change of U.S. administrations on Jan. 20 will impact the agreement. President-elect Donald Trump has raised concerns about Muslim immigration and most of Australia's asylum seekers are Muslims from the Middle East, Africa and Asia.

Crepeau, a Canadian law professor, said more countries should strike such multi-nation deals to find solutions for the global refugee problem.

"We don't know how it's going to develop, but I certainly hope that it develops in a way that offers refugees and asylum seekers solutions, and if it succeeds at emptying Manus and Nauru, I think this will be a great achievement," Crepeau told reporters in Canberra.

Immigration Minister Peter Dutton did not immediately respond to a request for comment.

Australia deters asylum seekers from attempting to reach its shores by boat, usually from Indonesian ports, by refusing to ever resettle them.

Crepeau made a scathing assessment of this policy on Friday as he ended an 18-day fact-finding mission in Australia that included two days on Nauru. Time did not allow a visit to Manus Island, where 873 men are housed in a male-only camp.

While the camps had opened their gates on the past year and were no longer detention centers, the asylum seekers still felt confined, he said.

The confinement on Nauru amounted to cruel, inhuman and degrading treatment or punishment, he said.

Children on Nauru showed signs of post-traumatic stress disorder, anxiety and depression. They suffered from insomnia, nightmares and bedwetting, Crepeau said.

"I would say that Australia would vehemently protest if its citizens were treated like this by other countries and especially if Australian children were treated like this by other countries," Crepeau said.