The French Polynesian president, Edouard Fritch, has added the leader of the opposition Atia Porinetia party, Teva Rohfritsch, to his ministerial line-up.
The public broadcaster says Mr Rohfritsch has been given a senior finance portfolio.
This comes as the once dominant Tahoeraa Huiraatira has further purged its ranks and excluded more key ministers while now defining itself as an opposition party.
Mr Fritch is officially still a Tahoeraa member as only one of two leaders elected by the party, which is led by Gaston Flosse.
Flosse, who lost office last year because of a corruption conviction, has spearheaded the exclusion of all party members who are siding with Mr Fritch.
Those purged in recent days include six ministers and one of the territory's members of the French National Assembly.
The expelled Tahoeraa politicians, which have formed a group within the assembly called Tapuna Huiraatira, now belong to no party.
Flosse says the Tahoeraa will from now on vote against the government, which now has only minority support.
At the last election, the Tahoeraa had won 38 of the assembly's 57 seats.