Fr Georgi Mamaladze was detained at Tbilisi airport on Friday, however, prosecutors have stopped shot of linking his arrest to a report of an alleged plan to poison the country's most senior orthodox leader.
The respected television channel Rustavi 2 earlier aired a programme which featured claims of a scheme to poison Patriarch Ilia, the head of the Georgian Orthodox Church (pictured above with Pope Francis).
Speaking to reporters, chief prosecutor Irakli Shotadze confirmed the arrest of Mamaladze but refused to be drawn on who the priests intended victim allegedly was.
At the time of his arrest, Mamaladze - who is a well known religious figure in Georgia - was his way to Germany where Patriarch Ilia has been receiving hospital treatment.
At 84 years old, the patriarch appeared frail when he welcomed Pope Francis to the country in October last year and he has been in poor health for several years.
Prosecutors say Mamaladze was arrested following a tip-off from a man who claimed that he had been approached by a priest interested in buying cyanide, a toxic substance.
Weapons were found when police searched his home.
Chairwoman of the parliamentary committee on legal issues, Eka Beseliya, said Mamaladze's arrest "has prevented a grave crime".
Explaining that the case is classified, Ms Beseliya refused to give further details but added that the patriarch's "security and health are protected absolutely".