Poland's right-wing ruler wins four more years

"We are finishing a certain stage: we are starting a new one. It is not easier, maybe more difficult. But I hope that it will be finished with even greater success," he added.

The PiS party "had a real plan ... for courts to stop being the ball and chain of the Polish economy," Zbigniew Ziobro, the PiS justice minister, said.

PiS won the elections to the lower house with 43.6 percent of votes, giving it an outright majority of 239 seats out of 260 under Poland's electoral rules.

It also won 46.2 percent of votes in the upper house, amid a high turnout of more than 60 percent.

Kaczynski's mention of a "certain stage" of reform alluded to PiS' overhaul of the Polish judicial system.

The comments by Ziobro, the main enforcer of those reforms, were more explicit in saying they would continue.

That augured badly for EU relations after the European Commission launched a sanctions procedure against Poland some two years ago, saying the changes were designed to make judges into PiS' political servants, undermining the independence of the courts.

PiS also attacked "liberal elites" in its campaign and promised to spend more on welfare.

And it hammered Poland's pro-LGBTI movement as a form of nefarious foreign influence in another assault on mainstream EU values.

The Civic Coalition (KO), a bloc of three centre-right and pro-EU parties, came second with 27.4 percent in the lower house and 33.2 percent in the senate.

"It's important that the winner [PiS] does not try to destroy its opponents, but understood that, after a win, all political forces need to live side by side," Donald Tusk, the outgoing president of the EU Council in Brussels and a former Polish prime minister, who campaigned on behalf of KO, said.

Polish democracy was "very strong and stable", Tusk added, even though PiS has also curtailed media freedoms and civil society in its past four years in power.

"We did not have the feeling that we competed in a fair fight, that our opponent used fair methods," Grzegorz Schetyna, the head of the Civic Platform, the KO's main party, said.

Meanwhile, a left-wing coalition called Lewica came third with 11.9 percent in the lower house.

Lewica included Spring, a new party led by Poland's first-ever openly gay politician, Robert Biedron, who is also an MEP.

"We are returning to parliament. We are going back to where the Polish left has always belonged," Biedron said as the results came out, showing a different side of Polish society.

A conservative agrarian party, the Polish People's Party, will also enter parliament with 9.6 percent.

A far-right party called Confederation will join them after winning 6.4 percent of the vote.

For his part, Piotr Buras, who works in Warsaw for the European Council on Foreign Relations (ECFR), a London-based think tank, said the election showed: "Europe cannot prevent Poland's or any other country's backsliding towards semi-authoritarianism".

But it could not ignore "the disastrous implications of such a scenario" and it ought to press ahead with punitive measures, he said.

The ECFR's Pawel Zerka said: "High levels of support for PiS should not be interpreted as a sign that Poles have become nationalist or xenophobic. Rather, it reveals an effective party machine".

"The opposition sought to frame this election around democracy, the rule of law and values of openness and tolerance. However, the cut through seems to have been on national economic growth," Zerka said.