Dodojon Atovulloev told RFE/RL by phone that he was stopped at passport control on August 20 and is being held in Tbilisi's airport after arriving from the Czech Republic.
Atovulloev said he was told he was detained at the request of Tajik authorities, who accuse him of extremism and terrorism.
Atovulloev is well-known for his reports that are critical of Tajik President Emomali Rahmon and members of his family.
Reporters Without Borders said on August 20 the Tajik authorities' request to arrest him was politically motivated.
Last month, Atovulloev was denied entry at Moscow's Sheremetyevo Airport, where he also arrived from Prague.
Atovulloev, who has lived in the Russian capital for the last 20 years, survived an apparent assassination attempt last year.
He was stabbed several times in a Moscow restaurant.
He believes the attack was connected with his journalistic work.