The Polish parliament late on Thursday adopted an amendment to the electoral code aimed at boosting voter turnout at this year's general election, a move the opposition argues is illegal and will benefit the ruling party.
Under the new law, more polling stations could be created in villages with as few as 200 inhabitants and buses to polling stations would have to be organised for people over 60 or with disabilities if no regular public transport is available.
Critics say the electoral code should not be changed in an election year, pointing to a Constitutional Tribunal ruling saying no significant amendments should be introduced six months before an election is called.
The bill needs to go through the upper house of parliament, the Senate, and be signed by the president to become law, so it will probably not come into force within that time.
Poland will hold parliamentary elections in October or November and while the ruling Law and Justice (PiS) party, which has strong support among older and rural voters, is still leading polls, its support is shrinking in the face of a cost of living crisis.
The leader of the main opposition party, Civic Platform, said changing rules in an election year "violates the basic principles of democracy".
"If (PiS) are ready ... to manipulate the electoral law in order to increase their electoral chances, it is easy to imagine that they will also be capable of other types of manipulation," Donald Tusk said.
PiS Deputy Speaker Ryszard Terlecki said the only purpose of the changes is to increase voter turnout.
Party leader Jaroslaw Kaczynski said last October that the government wanted to create several thousand more voting stations "so that people leaving church (on Sunday) can vote".
Analysts said that the influence of the new rules on election results were hard to evaluate at this stage, but such changes introduced so close to an election were illegal and would be difficult to implement.
"Our research shows that it will not increase turnout, the effect will be minimal ... if it were an honest idea, they would mostly increase the number of voting stations in places with high population density, in cities," said Anna Materska-Sosnowska, a political scientist at Warsaw University.
(Reporting by Anna Wlodarczak-Semczuk and Pawel Florkiewicz; editing by Jason Neely)