Baron Waqa, the president of Nauru, warned China and other global powers seeking to use the Pacific as their playground to compete with each other - that the Pacific will no longer tolerate any interference
"From this meeting in Nauru, going forward, we will not allow this kind of behaviour in our Pacific meeting space," Mr Waqa said.
Speaking to journalists at the end of the leaders' retreat on Wednesday night, the president did not mince his words when he condemned the behaviour of the Chinese diplomat, Du Qiwen, the head of the Chinese delegation who attended talks involving Dialogue Partners to the Forum.
China is one of the key regional grouping's 18 dialogue partners.
"His behaviour in front of our leaders, ministers and officials was uncalled for. Would he behave like that in front of his President? I doubt it. He disrespected the Pacific and its Leaders and our dialogue partners who had come to join us in our own meeting.
"Look at him, he is a nobody. He is not even a Minister and demanding to be recognised and to speak before the Prime Minister of Tuvalu. Is he crazy?
"We will go further than that. We will not only ask for a formal apology, we will actually take it up to the United Nations. Not only that I will mention it at the UN and every international meeting to raise our concerns about this incident.
"Never mind they are bigger than us, but they should not disrespect us," Mr Waqa said.
The Forum chair said dialogue partners needed to respect the protocols and values of the Pacific Islands Forum, if they want to be engaged with member countries.
"I have to be strong for our members because no one is to come and dictate to us. If you listen to the retreat today, even their friends do not agree with their action. They were disappointed."
In light of the disruption at the Nauru meeting, a suggestion to convene the Partners Dialogue at the Foreign Ministers Meetings instead of the annual Leaders' Summit had been proposed by Smaller Island State Leaders.
Forum Leaders have taken the suggestion on board and directed the Secretariat to work with the Forum Troika - Samoa, Nauru and Tuvalu - to review guidelines and format of the Pacific Islands Forum meetings and report back to leaders.
Tuvalu will be the host of the 50th Pacific Islands Forum Leaders meeting next year.