Kolesnikova and Znak were on Monday sentenced to 11 years and 10 years in prison respectively, leading to an outcry from Western countries, the Reuters news agency reported.
Maxim Znak. Photo: EPA/Ramil Nasibulin/BELTA HANDOUT via PAP
"The decision of the Belarusian authorities ... deserves firm condemnation," Polish Deputy Foreign Minister Marcin Przydacz said in a tweet.
"This is an open crushing of human rights and another step intended to intimidate Belarusian society," he added.
"This repression should not go unanswered," Przydacz also tweeted.
Polish President Andrzej Duda has voiced solidarity with Kolesnikova and Znak.
"Poland demands the unconditional release of all political prisoners," he said on Twitter.
"These people are imprisoned for fighting for an independent and democratic Belarus," Duda added.
Belarusian opposition leader Sviatlana Tsikhanouskaya has demanded that the two activists be immediately released.
Speaking at an economic conference in Karpacz, southern Poland, Tsikhanouskaya demanded an "immediate and unconditional release of all political prisoners," including Kolesnikova and Znak.
"There are 649 political prisoners. These are all innocent people that dared to challenge the dictator," she said in a tweet dated Sept. 7.
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Source: PAP, Reuters
Click on the audio player above to listen to a report by Radio Poland's Michał Owczarek.