The Melanesian Spearhead Group has formally appointed a Fijian diplomat, Amena Yauvoli, as director general of the body.
In a statement, the chair of the MSG, Solomon Islands prime minister Manasseh Sogavare, said Mr Yauvoli has been appointed and signed his contract.
Mr Yauvoli replaces Peter Forau who resigned four months ago.
But the move came as the Vanuatu government revealed that last week it nominated one of its diplomats, Roy Mickey Joy, for the position.
It said Mr Joy had been heavily involved in the work of the MSG for a long time.
The Vanuatu prime minister, Charlot Salwai, said the selection of the director general is meant to be done by the Leaders' Summit.
He said the constitution of the MSG requires that the selection be a fair, open and transparently competitive process.
Mr Salwai says any deviation from this runs the risk of bringing the MSG into disrepute.