The Nauruan government has tightened up its visitor visa process after media representatives allegedly entered the country on false documents.
The Pacific island nation's official Twitter account initially claimed ABC staff had used tourist visas to gain entry but quickly deleted the post.
"Every nation has requirements that those entering must do so honestly. Sadly deceptive behaviour from ABC disadvantages others," a deleted tweet said.
The Nauru government said holders of visitor visas to Nauru should contact the country's consulate in Brisbane for further information.
"No visas held by Australian and New Zealand workers who enter Nauru for legitimate work reasons are affected," the government said in a statement.
Nauru increased the cost of foreign journalists' visa applications from $200 to $8000 in 2014, an amount which is not refundable if the bid is rejected.
Australian Greens senator Sarah Hanson-Young said the visa changes demonstrated the paranoia of the Pacific island country.
"A North Korean style media blackout was bad enough, but shutting down access to all Australian and New Zealand visitors is an extreme response," she said.
"The Australian government should clarify whether it opposes this knee-jerk reaction or condones the ongoing media blackout on Nauru."
A spokeswoman for the ABC later said there was no ABC News journalist on assignment in Nauru.
ABC News journalists have applied through official channels for journalist visas to visit Nauru, not for tourist visas, she said.
A Department of Foreign Affairs spokeswoman said the government was seeking clarification from Nauru on the changes.
"Any Australian with questions regarding their visa for Nauru should contact the consulate-general of the Republic of Nauru," the spokeswoman said.
