In May last year, the Rudd government announced that it would initiate legal proceedings in the International Court of Justice (ICJ) against Japan over its whaling program in the Southern Ocean.

Japan maintains its whaling program is carried out for scientific purposes, refuting accusations by various environment groups that the primary purpose of its whaling activities is to service Japanese restaurants.

Under the statute of the ICJ, a party to a case before the court can nominate a representative to sit as a judge ad hoc to a specific case if it does not already have a representative on the bench.

The judge ad hoc has the same powers as the permanent members of the bench.

"Under the Statute of the Court, judges are to be persons of high moral character with qualifications, including recognised competence in international law," Attorney-General Robert McClelland said. "Professor Charlesworth undoubtedly fills these criteria."

Professor Charlesworth currently holds the positions of professor of international law and human rights and director of the Centre for International Governance & Justice at the Australian National University. She is also an Australian Research Council Laureate Fellow. She received her doctorate of juridical science from Harvard Law School, and was honoured by the American Society of International Law in 2006 as a joint winner of the Goler T. Butcher Medal for "outstanding contributions to the development of international human rights law".

Professor Charlesworth is currently the patron of the ACT Women's Legal Centre, the Victorian Foundation for Survivors of Torture, and Lawyers Without Borders.

In 2010 she oversaw a project that aimed to strengthen Australia's human rights system.

Australia has until May to file its initial pleadings in the case, with Japan then having until March 2012 to respond. The ICJ, which sits in The Hague, Netherlands, would not be expected to rule on the matter until 2013 or after.