Reports from French Polynesia say the veteran politician Gaston Flosse is set to be held in preventive detention for alleged corruption for four months.
Local television says this has been confirmed by the public prosecutor as his lawyers hope an appeal will bring about his release within days.
The former president was detained and transferred to Tahiti's Nuutania jail this week after losing his parliamentary immunity last week.
The reports say the first joint questioning with other suspects will get underway next week.
Among them is a French advertising executive, Hubert Haddad, who has already been in prison for six months amid suspicion that he paid kickbacks to Mr Flosse and his party to get public sector contracts.