Exit polls show the governing social-conservative Law and Justice party (PiS) has secured an outright majority in Poland's main legislative body with 43.6 per cent of the vote.
PiS can hope for 239 seats in the 460-strong lower house, the Sejm, according to the Ipsos research. In the outgoing parliament PiS had 240 seats.
If the polling is confirmed after the official tally, the "good change will continue", PiS leader Jaroslaw Kaczynski said at party headquarters, referring to their slogan when swept into power four years ago.
The party now has "a huge mandate" from the public to govern, Prime Minister Mateusz Morawiecki said, speaking after Kaczynski.
Morawiecki thanked Poles for participating in the election, "including those who voted for our competitors. We will try to convince them to our vision of Poland's development in the coming four years", he said.
The main opposition force, the Civic Coalition (KO), led by centrist party Civic Platform (PO), came in second with 27.4 per cent of the vote and can count on 130 seats in parliament, according to the exit poll.
PO will work on integrating the opposition and hopes it will win a majority in the Senate, PO leader Grzegorz Schetyna said. Exit poll data was not available for the upper house.
The Democratic Left Alliance (SLD) will return to parliament after a four year hiatus, with 11.9 per cent of the vote. SLD, which is in fact an alliance of three left-wing parties, can count on 43 seats in parliament.
The Polish People's Party (PSL), a Christian Democratic agrarian grouping, received 9.6 per cent of the vote and may hope for 34 seats.
Voter turnout reached 61.1 per cent according to Ipsos, which would represent the highest result since 1989.
Official results are expected on Monday.
Australian Associated Press