The candidate or the parties have to fund for their own campaign, the Electoral Commission is not mandated to ask each candidate or party to disclose their financial statement.
Therefore the answer to your questions is NO
Source: Email from Ms Takiakia Maatia, Chief Electoral Officer, Department of Justice, Kiribati, January 31, 2018
Between the two major parties, there had been allegations and counter-allegations made in Parliament of foreign contributions in the last elections.
Source: Mackenzie, Uantabo Neemia, National Integrity Systems Transparency International Country Study Report Kiribati 2004, Transparency International 2004, Blackburn South, Australia page 6