The French Polynesian president, Oscar Temaru, has created a ministerial post for one of his cousins, Hiro Tefaarere, who is an assembly member of his Union For Democracy.
Mr Temaru has taken some responsibilities away from other ministers and made Mr Tefaarere the minister of small enterprise, industry and mining.
The president says the move is aimed at strengthening his government.
The addition of an eighteenth minister comes after Mr Tefaarere's repeated challenges of the government leadership.
In April, he was the only member to defy party directives when the assembly president was elected.
He nominated himself as candidate but attracted only his own vote.
Mr Tefareere's elevation into the cabinet has vacated an assembly seat that will be filled by the next member on the party list, Lela Temauri from the island of Tahaa.