Nauru's former Chief Justice says New Zealand is continuing to support an unjust system and should speak more strongly against what he calls an appalling abuse of power.
Three opposition MPs have been arrested and charged, while other MPs have had their passports suspended following protests at parliament last week, which the government has dubbed a riot.
The government has also controversially banned Facebook and passed laws to curb protests and public assembly.
New Zealand provides 600-thousand US dollars a year to fund Nauru's justice system.
New Zealand's Foreign Minister, Murray McCully says he's deeply concerned about recent developments but doesn't want to put Nauru's judicial system under any further pressure by pulling aid.
But former Chief Justice Geoffrey Eames, who resigned after not being allowed to return to Nauru from his Australian base, says that's a weak response.
"It should not be supporting it, it should be saying 'this is an absolutely appalling abuse of power.' I think the minister has got to make himself so plain to the present government that they accept that a change must occur and unless something is done, well, New Zealand is propping up a system that is simply unjust."