Donna Parchment Brown
The Office of the Political Ombudsman says it has received a formal complaint of vote buying in Portland Eastern, which it is investigating.
Political Ombudsman Donna Parchment Brown would not say the source of the complaint.
She told RJR News she is interviewing persons in relation to the matter, and while it is unlikely to that a perpetrator will be found before Thursday's by-election, the investigations will continue after the polls to ensure the same problems can be avoided for future elections.
Mrs Parchment Brown said she is hoping electors will be allowed to go out freely on Thursday to vote in the by-election.
She reiterated that vote buying and vote selling are a breach of the law.
She also called for transport operators in the constituency to make themselves available to "help the electorate get freely and safely to the polling stations so they can exercise their hard-won franchise to vote in an election in Jamaica."