Samoa's Head of State, Afioga Tuimalealiifano Vaaletoa Sualauvi, called for a fresh ballot after a dramatic series of events following the first election in early April.
The FAST Party looked set to topple the incumbent Human Rights Protection Party (HRPP), before a controversial interpretation of Samoa's gender quota law saw the HRPP granted an extra female MP.
Both major parties now hold 26 seats.
The announcement of a second election to be held on May 21 has frustrated voters in the country, who will have to travel to vote in their constituencies.