It appears that the electoral legislation does not specifically spell out the FPTP system. The only section where it is mentioned is in s 79(7), which deals with recounts of votes. In any case, the Parliament's official website makes it clear that 'The members of Parliament are elected by secret ballot on a “first-past the post” universal suffrage system'.
78: The Chief Electoral Officer shall, by warrant under his or her hand, publicly declare the election of the successful candidate, together with the number of votes received by each candidate.
79(7): On receipt of the advice of the Court pursuant to subsection (6) but subject to section 81, the Chief Electoral Officer shall forthwith pursuant to section 78 declare to be elected the candidate then found by the Court to have received the highest number of votes, and shall revoke any warrant previously issued by him or her.