The New Zealand Prime Minister John Key says the crisis that has enveloped Nauru is worrying and pressure will be applied to the island's government this week.
Concerns about human rights and the rule of law have escalated since the arrests of several opposition MPs after a protest last month.
Pacific foreign ministers meet this week in Sydney and New Zealand's Murray McCully has already spoken of plans to speak with Nauru's President Waqa.
At the weekend Australian Foreign Minister Julie Bishop said Canberra wants assurances the Nauru Government is following the rule of law.
Mr Key says he wants both countries to apply some pressure to Nauru.
"A co-ordinated - I don't know if we need to be absolutely co-ordinated in what we do but a response from both Australia and New Zealand will be beneficial. Certainly what we see taking place up there is worrying to us."