Conservative Karol Nawrocki won Poland’s weekend presidential runoff election, according to the final vote count on Monday.

Nawrocki won 50.89 percent of votes in a very tight race against liberal Warsaw mayor Rafał Trzaskowski, who received 49.11 percent.

The race had Poland on edge since a first round of voting two weeks earlier, revealing deep divisions in the country along the eastern flank of Nato and the European Union.

An early exit poll released on Sunday evening suggested Trzaskowski was headed to victory before updated polling began to reverse the picture a couple of hours later.

The outcome suggests that Poland can be expected to take a more populist and nationalist path under its new leader, who was backed by US President Donald Trump.

Most day-to-day power in the Polish political system rests with a prime minister chosen by the parliament.

However, the president's role is not merely ceremonial. The office holds the power to influence foreign policy and veto legislation.

Nawrocki will succeed Andrzej Duda, a conservative whose second and final term ends on August 6.

Under the Polish constitution, the president serves a five-year term and may be re-elected once.

Prime Minister Donald Tusk came to power in late 2023 with a coalition government that spans a broad ideological divide – so broad that it hasn't been able to fulfill certain of Tusk's electoral promises, such as loosening the restrictive abortion law or passing a civil partnership law for same-sex couples.

But Duda's veto power has been another obstacle. It has prevented Tusk from fulfilling promises to reverse laws that politicized the court system in a way that the European Union declared to be undemocratic.

Now it appears Tusk will have no way to fulfil those promises, which he made both to voters and the EU.

Some observers in Poland have said the unfulfilled promises could make it more difficult for Tusk to continue his term until the next parliamentary election scheduled for late 2027, particularly if Law and Justice dangles the prospect of future cooperation with conservatives in his coalition. (AP)