The Prosecutor General's Office said on Thursday that the investigation was delegated to Vilnius prosecutors.
The request to look into Uspaskich's statements was made by the Judicial Council earlier this week.
Uspaskich said the judges who heard the Labor Party's bookkeeping fraud case are criminals.
In July, Uspaskich was found guilty of fraud and bookkeeping fraud and sentenced to four years in prison. He and other convicts in the case, as well as the prosecutors, filed an appeal against the verdict.
Should the verdict remain unchanged, Uspaskich would go to prison and have to compensate million of litas worth of damages caused to the state.