The Vanuatu minister for lands, Willie Jimmy, says the re-election of the prime minister Ham Lini as president of the National United Party may be challenged in court.
Mr Lini was re-elected to lead his party unopposed.
But Mr Jimmy rejects the vote which saw Mr Lini elected, saying his faction didn't vote at all.
Mr Jimmy says the party's national co-ordinator was suspended, and then replaced by Mr Lini's nephew, who then cut the number of eligible voters.
It's been claimed people from Mr Lini's home province of Penama want to control the National United Party.
But Mr Jimmy says the party's founder and former prime minister, Father Walter Lini, was from the northern province, and had made it clear that his party was a national party.