Former Vanuatu Prime Minister Barak Sope has accused the Electoral Commission of fraud.
Mr Sope's Melanesian Progressive Party is taking legal action in an effort to overturn the election results in at least three seats.
The Party is taking action after its candidate was relegated to eighth in a recount in the seven seat Santo constituency.
Vatambe Reme had been second when the declarations were made on Monday last week, polling around 800 votes.
But after the Union of Moderate Parties complained the Electoral Commission says an error of 401 votes had been discovered.
The Electoral Commissioner Sethy Regenvanu says how this happened is a mystery, but Barak Sope calls it unbelievable.
"He is saying that it is a mystery it is not a mystery but it was a miscount by them, so instead of suddenly our candidate lost 400 votes, he was second on top and came last and lost, so we're saying is the electoral office is involved in electoral fraud."
The MPP won just two seats in the election, but Barak Sope says they will challenge the results in five constituencies, and hope to win at least three.
The party won four seats in the 1998 poll.