The prime minister of Vanuatu, Edward Natapei, says he will seek a court order to stop a rival politician, Harry Iauko, from using the name of the Vanuaku Party.
This comes after party members held two congresses over the weekend with one choosing Mr Natapei and the other Mr Iauko as party president.
On return from Tongoa island, where the party met, Mr Natapei suggested that Mr Iauko and his backers form a new political party.
However, Mr Iauko maintains his claim that he has majority support among the Vanuaku party subcommittees.
The split has weakened Mr Natapei's side within the coalition government.
