The French Polynesian president, Gaston Flosse, has decided to lodge a defamation case against the opposition's Oscar Temaru.
This follows a news conference at which Mr Temaru said French Polynesia was for the first time governed by a gang of criminals, with a convict as its president.
Mr Flosse says the comments are offensive and pathetic.
Mr Temaru accused Mr Flosse of being the nation's most corrupt person.
Only months before being elected president this year, Mr Flosse was given two long jail sentences and hefty fines for corruption.
Mr Flosse was briefly jailed twice in 2009 as part of a probe in one of the cases.
He has appealed against one of the convictions in France's highest court, but should he lose, the 82-year-old politician may have to quit public office.