A global media rights group criticised Nauru on Wednesday for creating a "news black hole" around an Australian-funded refugee centre operating in the remote Pacific island nation.
Reporters Without Borders (RSF) also accused Canberra of failing to defend journalistic freedoms in relation to the camp, which it described as a "Pacific Gulag" and "Australia's Guantanamo".
RSF's Asia-Pacific head Daniel Bastard said Nauru had banned the Australian Broadcasting Corporation from covering an international summit next month on "completely specious" grounds.
He said the ban on the public broadcaster was the latest obstacle to be thrown in front of media wanting to cover Nauru and the controversial camp that Australia bankrolls.
"This island has become a news and information black hole because of the refugee processing centre it hosts for the Australian government," he said, calling for the ABC to be given accreditation.
"We also condemn the hypocritical silence from the Australian authorities, who have not lifted a finger to defend their public broadcaster."
Few foreign journalists have had access to Nauru over the past few years, with many hampered by the Aus$8,000 (US$5,800) charge per visa application, non-refundable even if not granted.
It has also severely limited how many journalists can cover next month's Pacific Island Forum meeting, restricting the total number of media workers to just 30.
AFP is among the media organisations that regularly cover the Pacific's largest annual diplomatic summit, but has been refused accreditation by Nauru.
Nauru argues its small size means it can only accommodate a few journalists, and denies the measure amounts to "restriction of press freedom".
However, media campaigners say preventing large numbers of journalists visiting for the summit also avoids scrutiny of the refugee detention centre, which is close to the meeting venue on an island that is only 21 square kilometres (eight square miles).
The facility was set up under Canberra's hardline immigration policy, which sees asylum-seekers who try to reach Australia by boat processed in offshore compounds.
It currently holds more than 240 men, women and children, and is an economic lifeline for the isolated nation.
The Nauru government did not respond to a request for comment on RSF's statement.