Maryna Adamovich, the wife of jailed ex-presidential candidate Mikalay Statkevich, told RFE/RL the meetings were held on November 7 in Brussels.
Natallya Pinchuk, the wife of prominent Belarusian rights defender Ales Byalyatski, also attended.
Byalyatski has been in prison since August 2011 and Statkevich has been held since December 2010.
The two women held talks with European Parliament President Martin Schulz, Polish member of the European Parliament Jacek Saryusz-Wolski, and European Commissioner for Enlargement and European Neighborhood Policy Stefan Fuele.
Both Statkevich and Byalyatski say the cases against them are part of a politically motivated crackdown against opposition figures by Belarusian President Alyaksandr Lukashenka.