The former chief justice of Nauru's Supreme Court has slammed the Australian Government for keeping quiet as Nauru abolished its highest legal appeal process.

The Nauruan Government secretly terminated the role of the Australian High Court as Nauru's final court of appeal, an arrangement that has been in place since the 1970s.

The move shocked the legal professions in both Nauru and Australia, as no notice of the change was given and an alternative appeals process is yet to be established.

Former chief justice, Australian Geoffrey Eames, said he had "no doubt whatsoever" that it was "politically motivated", given the timing has prevented critics of the Nauruan Government from appealing the outcomes of cases against them.

He was highly critical of the Australian Government too, given it was aware of the looming change but did not tell anyone.

"I think it's a disgrace that the Australian Government has kept this a secret," he said.

Former Nauru chief justice, Australian Geoffrey Eames. ( News Online Brisbane )

'This was a sucker punch'

In December last year, the Nauru Government quietly gave the Australian Government notice that it wanted to end the appeal arrangement.

The required 90-day notification period has passed, and no local appellate court has been established.

Hence, since mid-March there has been no avenue of appeal to Nauru's Supreme Court decisions.

This only became public knowledge after Nauru's solicitor-general mentioned it in an informal chat to Australian lawyers on a plane flight on Good Friday.

"I spoke to the president of [the] Law Society and the announcement came as a complete surprise to him," Mr Eames said.

"The fact that it was done in complete secrecy give us a fair clue, I think, to what our reaction should be.

The move directly affects a groups of Nauruans, including former opposition MPs, who were about to lodge appeals with the Australian High Court.

Their case relates to an ugly protest in 2015, where they criticised the Government for its earlier interference in the judiciary.

Former Nauru MPs Matthew Batsiua, Sprent Dabwido and Squire Jeramiah (L-R). ( Supplied/UN )

They had intended to appeal a succession of increasingly long jail sentences handed down by the Supreme Court, arguing the sentencing had been influenced by the Nauruan Government.

Mr Eames said it was "a scandalous situation".

"[The Nauru Government] must have known when they made this decision that they were going to destroy the appeal prospects of a group of people who were facing criminal charges because they were involved in attacks against the Government for its role in breaches of the rule of law," he said.

"This was a sucker punch."

The former opposition MPs have been on bail pending appeal, but that appeal avenue no longer exists.

They are scheduled to return to the Nauru Supreme Court on Thursday, and face the prospect being taken back into custody.

Mr Eames resigned as chief justice in 2014 after the Nauruan Government refused to issue him a visa to return to the country.

It was part of a series of events that saw political interference in the judiciary that prompted the protests that landed the then-opposition MPs in prison.