Conservative historian Karol Nawrocki appears to have edged ahead in Poland's presidential election, after a late exit poll overturned an early showing that gave a razor-thin victory to his rival, the liberal Warsaw mayor Rafal Trzaskowski.
A late exit poll by Ipsos for broadcasters TVN, TVP and Polsat showed Nawrocki at 50.7 per cent, and Trzaskowski at 49.3 per cent.
Earlier readings published just after voting ended had the eurosceptic nationalist at 49.7 per cent.
The vote is seen as a test of the nation's support for a pro-European course versus Donald Trump-style nationalism.
Official results were due on Monday, although a late poll that mixes some results with exit surveys was expected to be published overnight.
The exit poll carries a margin of error of two percentage points.
Nawrocki, 42, an amateur boxer who ran a national remembrance institute, campaigned on a promise to ensure the government's economic and social policies favour Poles over other nations, including refugees from neighbouring Ukraine.
Trzaskowski, 53, had promised to help the government of Prime Minister Donald Tusk complete its democratic reforms, which they both say aim to repair an erosion of checks and balances under the previous nationalist government that lost power in 2023.