The race for Brazil's October elections officially opens Tuesday with dueling campaign events by far-right incumbent Jair Bolsonaro and leftist ex-president Luiz Inacio Lula da Silva highlighting the South American giant's deep divides.

Front-runners Bolsonaro and Lula, who have in reality been on the campaign trail for months, will make it official with rival events showcasing their polar-opposite styles.

Bolsonaro, 67, plans to launch his campaign with a rally in Juiz de Fora, the small southeastern city where an attacker stabbed and nearly killed him during his 2018 campaign.

The attack cemented Bolsonaro in the minds of die-hard supporters as "The Myth" -- a hero swooping in to rough up the political establishment and speak his mind with tough-talking clarity.

It is an image that has suffered as Bolsonaro has lurched through a series of crises, from the coronavirus pandemic -- which he insistently downplayed, even as Brazil's death toll surged -- to soaring inflation that has come as a gut-punch to Brazilian families.

Lula, 76, who leads in opinion polls, will meanwhile start his campaign with a visit to a Volkswagen plant in Sao Bernardo do Campo, in the industrial heartland of Sao Paulo state, the place where he launched his political career as a union leader.

Both events are dripping with symbolism, said political analyst Adriano Laureno, who called the race "the most polarizing presidential election since the return to democracy" in Brazil in the late 1980s.

"Bolsonaro has tried to build this narrative of divine selection around his presidency... in which surviving the stabbing incident plays a central role," said Laureno, of consulting firm Prospectiva.

"Lula meanwhile always looks to return to Sao Bernardo at key moments in his political trajectory, casting himself as a man of the people," he told AFP.

Lula currently leads with 44 percent of the vote to 32 percent for Bolsonaro, according to the latest poll from the Ipec institute, published Monday.

If no candidate wins more than 50 percent of valid votes in the October 2 election, a runoff will be held on October 30.

The country of 213 million people has been torn in a two-way race since March last year, when Brazil's Supreme Court annulled a controversial corruption conviction that had sent Lula to jail and sidelined him from politics.

The ex-president (2003-2010) left office as the most popular president in Brazilian history, after presiding over an economic boom that helped lift some 30 million people from poverty.

But he fell spectacularly from grace when he became a target in "Operation Car Wash," a massive investigation into systematic corruption centered on state-run oil company Petrobras.

Lula, who denies wrongdoing, calls the case a trumped-up bid to topple his legacy.

Bolsonaro is counting on a big new welfare program to boost his popularity and close the gap with Lula.

It is still too early for the program's full effect to be reflected in polls.

Many Brazilians fear if Bolsonaro loses he will follow in the footsteps of his political role model, former US President Donald Trump, and try to fight the result.

Bolsonaro, who regularly blasts alleged fraud in Brazil's electronic voting system -- without evidence -- is fond of saying "only God" can remove him from office.

The two candidates could cross paths late in the day, at a ceremony in Brasilia to install the new head of the Superior Electoral Tribunal.

Both Bolsonaro and Lula are invited.