New Zealand's former foreign minister Phil Goff has called on Australia to speak out over the resignation of Fiji's police commissioner Ben Groenewald.
Mr Groenewald resigned this week after accusing the Fiji military of interfering with "policing".
"I think it's really important that maybe not in a public way, but certainly in a direct way, that high commissioners from Australia and New Zealand indicate their concern about that development," Mr Goff told the ABC's Pacific Beat program.
"We had elections that were deemed to be fair and free last year, an operating parliament that's trying to find its way, but this is a step backwards for Fiji."
Mr Groenewald said his resignation was "indirectly" related to a case of alleged police brutality.
A video emerged online three years ago apparently showing Fijian officials beating several prison escapees with wooden and metal poles.
An investigation into the beating has been completed and the case referred to public prosecutors, according to local media.
Mr Goff also expressed concern that Mr Groenewald would be replaced by a senior military officer, Lieutenant Colonel Sitiveni Qiliho.
Amnesty International spokesperson Rebecca Emory also said Mr Groenewald's resignation was a "concerning development".
"We saw the commissioner as having taken some very positive steps towards addressing impunity in Fiji and we were hoping the work he was doing would continue," she said.
"We're calling on the Fiji government to ensure this happens."