Duda already pardoned them in 2015, though legal experts argued these pardons were illegal at the time.
ADVERTISEMENTPoland's president said on Thursday that he has started the process to once again pardon two politicians arrested earlier this week, amid a bitter stand-off between the new government and its national conservative predecessor.
The development came as tens of thousands of people with anti-government banners and Polish flags gathered for a protest in front of the parliament building in Warsaw.
The demonstration was organised by the now opposition party Law and Justice (PiS), which held power for eight years until last month and is closely aligned with President Duda.
Law and Justice, frustrated over its recent loss of power, urged its supporters to protest moves by the new pro-European Union government to take control of state media.
It also said it was protesting the arrests on Tuesday of the two senior party members who served in government, former Interior Minister Mariusz Kaminski and his former deputy, Maciej Wasik.
Kamiski and Wasik were convicted of abuse of power for actions taken in 2007, when they served in an earlier PiS-led government.
Duda pardoned them in 2015, though legal experts argued the pardons weren't legal, because presidential pardons are reserved for cases that have gone through all appeals.
This wasn't the case then.
In June, Poland’s Supreme Court overturned the pardons and ordered a retrial. Kaminski and Wasik were convicted and sentenced in December to two years in prison.
Police on Tuesday arrested them while they were at Duda's presidential palace, where they had received protection for much of the day.
Duda had long maintained that his first contentious pardons in 2015 were legal, and he didn't need to pardon them again. But on Thursday, he said he was initiating clemency proceedings for the two men at the request of their wives.
This time, Duda appealed to the justice minister, who is also the prosecutor general, to approve their pardons and to release the two men from prison while the decision was being made.