Warsaw's liberal mayor Rafal Trzaskowski won a narrow victory in Poland's presidential election, according to an exit poll, but a second-round run-off with conservative historian Karol Nawrocki will be required in two weeks' time to decide the country's next president.

Warsaw's liberal Mayor Rafał Trzaskowski will face off against conservative rival Karol Nawrocki in Poland's run-off presidential election, after less than two percentage points separated the candidates in Sunday's first-round vote.

The mayor of Warsaw was poised for a narrow win over a pro-Donald Trump nationalist in the first round of Poland’s presidential election that is critical for the pro-European government’s agenda to undo years of populist rule.