Vote counting in Brazil's presidential race has wrapped up, with incumbent Luiz Inácio Lula da Silva facing a narrow margin against Flávio Bolsonaro — the eldest son of former president Jair Bolsonaro and now a senator — in the contest to lead the country.

Ballots cast on Sunday extended beyond the presidential race, with approximately 160 million enrolled voters taking part in a contest that also placed legislative seats, governorships, and senate positions on the line, news reports indicated. Tabulation of votes is expected to move quickly once polling stations close, given that Brazil relies on an electronic balloting infrastructure.

Under electoral rules, should neither of the leading contenders clear the 50 per cent threshold of valid votes cast, the pair would face each other again in a run-off ballot scheduled for 25 October, according to broadcast reports.

Pre-election polling across most surveys pointed to a tight race, with Lula carrying a narrow advantage over Flávio Bolsonaro — a gap that appeared to tighten still further when projections modelled a potential runoff scenario.

Flávio Bolsonaro travelled to Rio de Janeiro to cast his ballot on Sunday, stating that the country stood in need of transformation and that he hoped to see the population gain greater freedom. Citing heavy tax burdens and the ongoing deaths of women as conditions the country could no longer absorb, he told a broadcast outlet that a first-round victory remained within his reach.

Having held Brazil's presidency across two terms between 2003 and 2010, the 80-year-old Lula is campaigning on an agenda centred on tackling the country's deep-rooted economic disparities. Tighter ties with the United States under Trump's presidency are among the commitments he has put forward.

Bolsonaro's father — who previously held the country's highest office — now faces a 27-year prison sentence after prosecutors established his role in a conspiracy to nullify the 2022 election result, a vote he lost to Lula by fewer than two percentage points. Verdicts handed down against Jair Bolsonaro and a number of military officers have prompted debate over the resilience of Brazil's democratic institutions, while also drawing attention to the country's two-decade experience under a military government that received backing from the United States.

Voter concerns over public safety, everyday affordability, and the threat of crime have taken a prominent place at the centre of the presidential race. Questions about the extent of US involvement in Brazil's internal affairs, alongside ongoing corruption matters, have persisted as topics drawing public and political attention, according to broadcast reporting.

A Quaest poll placed public safety at the top of respondents' concerns, drawing 31 per cent, while corruption came in at 20 per cent, economic conditions at 19 per cent, and access to healthcare at 12 per cent.

Tallies from the automated count will show whether either contender clears the absolute majority threshold or whether voters return to the polls on 25 October for a runoff.