The International Commission of Jurists says the rule of law is broken in Nauru and neighbouring countries should voice their concerns.
Four Nauru MPs are facing court and have had their passports cancelled, including Roland Kun, who has not been charged with any crime.
His lawyer David Lambourne, who has been blocked from entering Nauru, says the Justice Minister, David Adeang, is pursuing a personal vendetta against elected MPs.
John Dowd is the President of the ICJ Australia, and he says the international community must react when there's evidence that the judiciary is not independent and the court process is not respected.
"Clearly the rule of law is not being allowed to function, whether it's through the Justice Minister or through any of the ministers and therefore all neighbouring countries including Australia has to voice its concern."
A former resident magistrate who was deported last year, Peter Law, says the rule of law has totally broken down.
Australia has been told its lack of public criticism of Nauru is appalling.
John Dowd says Australia's asylum seeker detention centre on Nauru means it has stayed relatively silent.
"Clearly it's in Australia's political interests to be able to use Nauru irrespective of what's going on there. Australia doesn't want to have to deal with the people that are held on Nauru. We are obviously compromised and I think Australia has acted appallingly in not making a greater fuss."
John Dowd says Australia's Prime Minister or Foreign Minister should visit Nauru and see the situation for themselves.