Brazilian presidential candidate Flavio Bolsonaro casts his vote in Rio de Janeiro as the country holds its general election on Sunday, October 4.

The race pits incumbent President Luiz Inacio Lula da Silva of the Workers' Party against Bolsonaro, a senator and eldest son of former President Jair Bolsonaro - campaigning on tougher measures against organised crime, tax and spending cuts and a smaller government.

Backed by his father, Bolsonaro also supports an amnesty that could benefit the former president and others convicted over efforts to overturn the 2022 election result. Jair Bolsonaro is serving a 27-year prison sentence over a failed coup plot and is barred from holding public office.

Nearly 159 million Brazilians are eligible to vote, with a runoff on October 25 if no presidential candidate wins more than 50 per cent of valid votes.