The Belarusian Association of Journalists said three members were prohibited from leaving the country.
"Not a single official department would give journalists any information about who have imposed these temporary restrictions on international travel," the association said in a statement. "A number of political and civil activists have also faced the same problem."
U.S. and European leaders last year condemned an alleged growing culture of repression in Belarus. Hundreds of challengers to President Alexander Lukashenko were rounded up following elections in December 2010.
The BAJ said some members had freedom of movement restricted and the group was the subject of "defaming information" from members of the country's state-run media.
"The organization will keep on doing its activities on establishing freedom of speech in the country, regardless of the pressure," it pledged.