The pro independence movements of New Caledonia and French Polynesia have issued a statement jointly opposing a French initiative aimed at integrating the two territories into regional organisations.
The two leaders, Oscar Temaru and Roch Wamytan, say they refuse to carry the message from France.
They accuse France of using a chequebook policy in a bid to influence the Pacific Islands Forum's admission process so that French Polynesia can join as an observer.
To qualify, a territory has to be on its way to independence, but French Polynesia is no longer on the UN list of territories to be decolonised.
Members of the Forum are being warned against the French-backed advances of French Polynesia's Gaston Flosse.
To lobby for support, Mr Temaru will this week meet the leaders of the Melanesian Spearhead Group at their summit in Solomon Islands.