Nauru's justice system is in disarray and cases against scores of asylum seekers are in limbo after the Nauru government sacked its only magistrate and denied its Australian chief justice a visa to re-enter the country.

The government moved without warning against the Australian magistrate Peter Law on Sunday, terminating his employment and escorting him in police custody to the airport, without giving him the chance to pack or close his flat.

Injunction ignored: Geoffrey Eames, Nauru's chief justice. Credit:John French

It then ignored an injunction aimed at preventing Mr Law's removal issued by Nauru's chief justice, Geoffrey Eames, a former Victorian Supreme Court judge, who has expressed concern that the dismissal was politically motivated and an abuse of the rule of law.

Justice Eames was due to fly to Nauru last night but was told his visa had been cancelled, apparently on the order of Nauruan president Baron Waqa. He is believed to be considering challenging the cancellation in the Australian High Court.