Two independent television channels aired video footage showing guards at Gldani Prison No. 8 beating a prisoner and sodomizing him with a broom handle, Radio Free Europe/Radio Liberty reported Wednesday.
The six-minute video was shown just hours after the Georgian Interior Ministry reported three guards at the same prison had been arrested for inhumane treatment.
The minister responsible for overseeing Georgia's prisons was sacked and his superior later submitted her resignation to the prime minister.
Human Rights Watch has called on the government of Georgia to conduct a prompt, thorough and independent investigation into the abuse.
"The abuse captured in this footage is profoundly disturbing," said Giorgi Gogia, senior Europe and Central Asia researcher for the group.
The European Committee for the Prevention of Torture said in a 2010 report that former inmates of Gldani prison alleged staff punched, kicked and struck them with truncheons during the intake process and as punishment for talking too loud or attempting to communicate with inmates in other cells.