Ian Castaldi Paris and Rachel Tua have submitted their nominations for a casual election on the eighth district to fill the seat in parliament previously occupied by Labour MP Chris Cardona.
The former economic services minister resigned after having been kept out of the Cabinet by Prime Minister Robert Abela in January.
Castaldi Paris, a notary, is seen as the favourite to win the contest. He is a former Nationalist mayor of Lija who also headed the PN's College of Councillors before crossing to the Labour Party in 2015. He recently served on the board of Air Malta.
In 2009 a man who tried to set fire to Castaldi Paris's house turned into a ball of fire himself after his clothes, probably soaked in flammable liquid, burst into flames.
Dramatic CCTV footage showed the silhouette of what appeared to be a man walking up to the door and then getting engulfed by flames before he ran out of the camera's line of vision still ablaze.
Rachael Tua, a lawyer, served as the Labour Party’s equal opportunities officer.
Vote-counting will take place at Naxxar counting hall on Wednesday morning.