French Polynesia's opposition Tahoeraa Huiraatira Party says it considers that letters written by the former finance minister, Georges Puchon, to the party leader to be tantamount to his resignation.
In February, Mr Puchon failed to back Gaston Flosse in his bid to stay in power after he lost the Tahiti by-election.
Mr Flosse was ousted in a no-confidence vote days later after refusing to honour a pre-election promise to step down in case the Tahoeraa didn't win a majority in the territorial assembly.
According to a report by the Tahitipresse news agency, Mr Puchon has taken issue with the party's interpretation of his letters, saying he never resigned.
He had earlier said he was prepared to work with the government of Oscar Temaru following a call by Mr Flosse to form a government of national unity.
The party has also dropped Jean-Alain Frebault after he defected to the Temaru camp and voted against Mr Flosse in the no-confidence vote.
Last year, Mr Frebault voted with Mr Flosse to oust the Temaru-led government.