The United Nations High Commissioner for Refugees said it will appeal to appear in a High Court challenge against the Abbott government on its handling of asylum seekers.
UNHCR said that it will appear to assist the court on points of international law.
George Newhouse, a lawyer representing the asylum seekers said that the case shall test the power of the Abbot government to "to intercept a boat on the high seas, hold the passengers virtually as prisoners for a month and then attempt to send them back to another country".
"This is a case that has never been tested before and the power of the government to undertake such action is in question. This has important implications not just for Australia, but for all nations, and it's likely that we will see intervention from human rights bodies both here and internationally," Mr Hewhouse told press Thursday.
The full court hearing to the case was set for Oct 14 and 15.
The Human Rights Law Centre's director of legal advocacy, Daniel Webb, expressed the impact of the government's treatment to the 50 children who were forcibly taken to Nauru.
"There are 50 children in this group who have endured a truly wretched few months. First they were detained at sea. Then they were secretly and forcibly taken away to Nauru. Now they're languishing in detention on a remote Pacific island in conditions the UN has described as inhumane and unsuitable for children," Webb said.
Meanwhile, a fourth and final public hearing of the National Inquiry into Children in Immigration Detention happens on August 22, 2014 in Canberra.
On Wednesday, President of the Australian Human Rights Commission, Professor Gillian Triggs, welcomes the announcement by the Minister for Immigration and Border Protection, Scott Morrison, that children under the age of 10 and their families will be released from locked detention into the community by the end of 2014.
However, Triggs said that the announcement meant that the plight of children over ten years old and their families who had been staying in the detention for over a year remains in a limbo.
Triggs said that there are approximately 500 children in Australia after July 19 and thus will remain in indefinite detention with the current policy on asylum seeker. The majority of these 500 children are staying in detention cell not fit for them. Data from the detention health services shows that these children have deteriorating mental health.