Early exit polls suggested opposition centre-left candidate Orsi had secured 44% of the vote, followed by Delgado's 27% for the ruling coalition and 16% for young conservative social media expert Andres Ojeda.

Early exit polls in Uruguay's election suggest centre-left opposition candidate Yamandu Orsi is ahead of conservative rival Alvaro Delgado and a run-off vote is likely to be needed for a direct duel.

Orsi had obtained 44% of the votes, according to an exit poll by Cifra, followed by Delgado's 27% for the governing coalition and 16% for the young conservative social media expert Andrés Ojeda.

Ojeda has previously pledged to support Delgado to prevent the left from returning to power if it is eventually eliminated.

Before the election, pollsters had indicated that no presidential candidate was likely to win more than 50% of the vote, meaning a runoff would be held on November 24 between the top two finishers on Sunday.

Meanwhile, according to local pollster Cifra, 61% of eligible voters rejected a proposal to reform Uruguay's $22.5 billion private pension system, make pensions more generous and lower the retirement age by five years to 60, while 39% voted in favor.

Sunday's controversial plebiscite requires a simple majority to pass.