The governing Law and Justice (PiS) won the parliamentary ballot, with 43.6 percent of the vote, and appeared headed for a second term in power, according to an exit poll released seconds after voting ended on Sunday.
State broadcaster TVP reported that such a result would give the ruling conservatives 239 seats in the 460-seat lower house of parliament.
The official election returns were expected to be announced by Tuesday.
Law and Justice leader Jarosław Kaczyński, whose party came to power in a landslide victory in late 2015, told cheering supporters on Sunday: “We’ve won; we’ve managed to win despite a powerful front against us.”
He added: “If the poll results pan out, we will have another four years in government ahead of us.”
Kaczyński also said: “We have four years of hard work ahead of us because Poland must continue changing, and it must be changing for the better.”
The largest opposition bloc, the Civic Coalition, led by the Civic Platform (PO) party, was runner-up in Sunday’s election, with 27.4 percent support, according to the exit poll.
A block of three leftist parties led by the post-communist Democratic Left Alliance (SLD) finished third on Sunday with 11.9 percent, according to the exit poll, a result that opens the way for a left-wing grouping to return to parliament after a hiatus of four years.
The Polish Coalition of the rural-based Polish People’s Party (PSL) and the anti-establishment Kukiz’15 grouping finished fourth with 9.6 percent, the poll found.
The right-wing nationalist Confederation group, with 6.4 percent, also crossed the 5-percent voter support threshold that Polish parties need to clear to enter parliament.
Turnout was 61.1 percent, according to the exit poll.
Source: TVP, PAP