Dan McGarry from Vanuatu's Daily Post newspaper told the ABC he won't be attending.
"The implication here is that anybody who provides negative coverage is going to be treated exactly the same way as the ABC and that is just not on," said McGarry.
"We can't accept that kind of conditionality in our reporting. So for us it is a no brainer it is an obvious decision to make."
The Nauru government is refusing to issue ABC journalists visas because of allegations of interference in its politics, bias and false reporting.
Australian journalists have been allocated a pool of just three media representatives to cover the forum, half the amount of New Zealand.
The ABC planned to send someone as part of a three-person Australian pool to the September meeting.
But Nauru's government said the ABC would not be granted a visa under any circumstances, blaming the ABC for interfering in domestic politics and harassing its president, among other allegations.
The ABC's head of news said the broadcaster is outraged, adding that it does not intend to vacate its position in the media pool.
The Australian Prime Minister said he will still attend the Pacific Islands Forum meeting in September despite the host nation Nauru's ABC ban.
Malcolm Turnbull said while its position was unfortunate the sovereign rights of Nauru must be respected.
"It is up to Nauru who comes into their country, just as it is up to my government, who comes into Australia. So we respect their sovereignty but obviously we prefer to have events like this open to all the media," Mr Turnbull said.
Photo file. Caption: Nauru Airport