Reports from New Caledonia say the growing rifts within the anti-independence camp could bring down the government formed two months ago.
The Future Together Party's leaders are split over the Paris-sponsored deal to reconcile with the traditionally dominant anti-independence Rassemblement-UMP.
The Nouvelles Caledoniennes newspaper says the row may lead to the ouster of the newly elected president, Harold Martin, from the presidency and the party leadership.
The dissent was heightened by last week's visit of the new French overseas territories minister, Christian Estrosi, who warned Future Together Party against undoing the unity deal.
The minister's visit to Noumea also saw disagreements between Mr Estrosi and the French high commissioner over how to deal with strikes and protests, with the minister suggesting a new tough line which critics say could lead to unrest.
The high commissioner has subsequently resigned.
Both Mr Martin and Mr Estrosi are taking part in Forum discussions in Tonga this week.