But Tantowi Yahya, the spokesman for his rival, Prabowo Subianto, said it was far too early to make the call.

Mr Joko thanked his volunteers and urged them to watch the integrity of the official count against possible corruption.

"We are all grateful that based on the counting of quick counts, Jokowi-JK has won," he said to a packed room of supporters.

"I think now it’s time for us to guard the counting, from the lowest level to the highest, so that it’s clean and honest and there’s no intervention. We ask for the people of Indonesia to guard the purity of the people’s aspiration, and so that nobody can try to stain what people have voted for."

A number of polling companies are authorised to make quick counts, which include counting actual ballot papers, and which in the past have proved very accurate.

However, the claim of victory comes earlier than expected because many of the votes counted come from sparsely populated eastern Indonesia, where polling booths closed earlier, and not from the population centres of Java and Sumatra.

Earlier in the day on the streets of Jakarta, people lined up to vote for either Prabowo Subianto’s toughness or Joko Widodo as the man of the people.

“Jokowi is for the people, a leader who is born from the people and he's for the people,” said Hery Wijaya, sitting with friends in inner-city Glodok.

Tanah Abang market stallholder Eti said: “I voted for Prabowo because I know Prabowo follows Suharto. He's firm, he's military. I want Indonesia to revive, be spirited, not just lame, so I want a firm leader, not a lame one.”

However, in Chinatown, which was razed during the turmoil of Suharto’s 1998 downfall, with hundreds dead and dozens of women raped, it is Jokowi all the way.

“We experienced it ourselves,” says Wini, with her husband Derry, who are part of Indonesia’s ethnic Chinese minority.

“My parents lost their shops … We are still traumatised, and Mr Prabowo is more identified with [Suharto's dictatorial] New Order, so we want some change; and we don't want to go back to the old times.”

Turnout was expected to top 80 per cent of 190 million eligible voters in the world’s third-largest democracy, which some are saying faces a battle between its autocratic past and its democratic future.

Former general Mr Prabowo, accompanied by his son – Suharto’s grandson, Didit Prasetya – voted near his home in Hambalang, Bogor. He showed up to the polling booth at the local police station in a white Lexus, accompanied by two police on horseback.

Jakarta Governor Mr Joko and his wife Iriana voted in Menteng, near the governor’s mansion, which he will return to if he should lose the vote for president.

Neither man spoke to waiting media.

The final result will not be known officially for weeks, but “quick count” and exit polling companies are producing results even before the ballot closes, so unofficial results should be known by mid-evening Australian time on Wednesday.