The dominant French Polynesian Tahoeraa Huiraatira Party will decide this week whether to expel three members who defied party instructions during last week's election of a new assembly president.
Edouard Fritch was chosen in a third round by defeating the Union of Democracy candidate, Antony Geros, but in the second of the three rounds of voting three Tahoeraa member refused to vote in line with the
instructions given by the Tahoeraa leader, Gaston Flosse.
The President, Gaston Tong Sang, has now challenged Mr Flosse to exclude him from the party if it decides to expel the three members.
The opposition's Oscar Temaru says the ruling coalition is imploding, with the Tahoeraa losing nine of its 27 assembly members in less than two years.
He also says they are in the world's only democracy where both the president and the head of the assembly continue in office while being at the centre of serious fraud probe.
Mr Tong Sang and Mr Fritch are being investigated for their role in a 2002 purchase of a remote atoll from an associate at a grossly inflated price when they were in government.
In 2005, police investigators banned all communication between the two of them but eased the restriction because it would have jeopardised their jobs as assembly members.
The investigations, which have been extended to also questioning Mr Flosse about the deal, are in their second year.
It's not known when the police probe will be concluded.