The Fiji police say they are investigating the prime minister, Rear Admiral Frank Bainimarama, for being in breach of a regime decree and a law pertaining to the election promised for September.
If convicted for any of the breaches, he could face up to 10 years in jail.
The complaints were lodged by the United Front for a Democratic Fiji.
Rear Admiral Bainimarama is being investigated for campaigning without having his party registered, in contravention of the Political Parties Decree.
He is also being investigated for allegedly displaying Fiji's coat of arms on his campaign bus, in breach of the Coat of Arms of Fiji Act.
The Electoral Commission, which is tasked with supervising the process leading up to the polls, is yet to comment.
The election supervisor says he wants to have the names of candidates by August the 18th and then check if they are allowed to stand.
The Attorney General, Aiyaz Sayed-Khaiyum, has rejected claims that the use of the emblem on Rear Admiral Bainimarama's Fiji First party bus is in breach of the Coat of Arms of Fiji Act, saying the UFDF is trying to seek publicity.
It is not known if the police are investigating the media outlets which reported Rear Admiral Bainimarama's campaign in breach of the Political Parties Decree.