Agus Yudhoyono protests explosive allegations against his father on eve of election

The explosive allegations topped off one of the most incendiary election campaign periods in Indonesia's history, which many consider was a proxy war for the 2019 presidential election.

Antasari Azhar, a former anti-corruption commissioner who was jailed in 2010 for murder but recently granted a presidential pardon, alleged on Tuesday that SBY - as the former president is known - had been the "initiator" of his murder case after he refused his request not to detain Agus' father-in-law.

After casting his vote in South Jakarta, Agus said the claims had intentionally been made one day before the vote.

SBY, who has already vowed to take legal action against Antasari, said it was difficult to believe the "slander" was not related to the Jakarta gubernatorial election.

"I think it's extraordinarily cruel, but we stay strong, we are not too affected," Agus said as he cast his vote. "God willing, Jakartans are smarter, with hearts that can differentiate between lies and facts."

Agus, a handsome former military officer who was plucked from relative obscurity to stand for governor, has seen his electability dive in polls after uninspired performances in debates.

Australian National University lecturer Ross Tapsell said although Agus led on polls for the best-looking candidate, "that's never going to win you the election, even in the era of Instagram and Twitter and so on".

"Agus was was always going to have to perform at the debates and the general consensus was that he hasn't," he added.

His father has also proven something of a liability during the campaign period, with hyperbolic Twitter outbursts that have been ridiculed on social media.

SBY has emotionally railed against rumours that he was behind a November 4 mass rally that called for incumbent governor Basuki Tjahaja Purnama, widely known as Ahok, to be jailed for allegedly insulting Islam.

When students protested against sectarianism outside his house, SBY tweeted: "I ask the president, the police chief, do I not have the right to live in my own country, with the human rights that I am entitled to?"

This resulted in an avalanche of satirical tweets such as "I'm asking Mr President and Police Chief: why am I still single?"  ​and "I'm asking Mr President and Police Chief, why I am always sleepy during work hours?".

However Fadli, an 18-year-old who was casting his vote for the first time at a polling booth in Tanah Abang in Central Jakarta, told Fairfax Media that Agus had won his vote.

"He looks firm, he keeps his words," Fadli said, showing us the purple ink stain on his finger Indonesians use to denote someone has voted. "An army officer usually says A when he means A. I hope he can make Jakarta better."

Agus' promise to develop Jakarta without the controversial evictions to relieve flooding, create new parks and eliminate vice that have characterised Ahok's tenure was the policy that most appealed to Fadli.

However he had also been tempted by the third candidate, Anies Baswedan, who said he wanted to build a sports stadium for football.

More than 41.2 million Indonesians across seven provinces in Indonesia will vote for their leader for the next five years in Wednesday's election.

However all eyes have been on the capital, where 7.1 million Jakartans are eligible to vote in an election seen by many as a test of Indonesia's much vaunted pluralism and religious tolerance.

Ahok, who is Christian and ethnically Chinese, has been fighting an election campaign whilst simultaneously fighting to stay out of jail at his trial for blasphemy.

Religion is writ large in the election. Posters hung on the polling booths with profiles of the candidates list religion alongside their date and place of birth, education and assets in both rupiah and US dollars.

Of the six gubernatorial and vice-gubernatorial candidates in Jakarta, Ahok is the only non-Muslim.

Monganiah, a witness for Anies Baswedan's ticket at the Tanah Abang polling booth we visit, said Agus and Anies were the favourites in the area because Islamic sentiment was strong.

"Ahok's good, but because of the religious blasphemy case his electability decreases," she said.

Voting is voluntary in Indonesia. In the 2012 Jakarta gubernatorial election there was a 63.7 per cent voter turnout in the first round, with commentators expecting participation to increase this year.

Even businesses are doing what they can to encourage participation in the process.

Voters who go to Bakerzin, an Indonesian bakery, are given free packets of macaroons if they can show their "pinky blue finger".

Tari Lestari, supervisor at a central Jakarta branch, told Fairfax Media the promotion was to celebrate democracy in their country.

"It is a memorable moment for Indonesia," she said. "We are definitely doing this to encourage people to vote."

with Karuni Rompies and Jessie Chiang