The Nauru minister for foreign affairs, David Adeang, says he expects to impose a visa penalty fee on the Australian government next week for Iraqi refugee, Mohammed Sagar.
Nauru last month protested about the ongoing detention of two Iraqis who had been held on the island for nearly five years.
One of those men, Muhammad Faisal, is now in Australia receiving psychiatric care, but Mr Sagar remains on the island.
An earlier report said the Nauru government had decided to charge Australia a monthly fee of 75 000 US dollars following the expiry of Mr Sagar's visa at the end of last month.
But Mr Adeang would not confirm this.
He says it is a sensitive matter that is still being discussed by the two governments.
"I expect that new visa fee will be imposed from Monday onwards. We have indicated to them that the fee would be substantially greater than the new visa fees that are applied for the eight new Burmese refugees. In terms of whether they are willing and able to pay this new visa fee for Mr Sagar is a matter of discussion between our two governments. The matter is yet to be resolved."
An Australian immigration official declined to comment on the issue.