Incumbent president Joko Widodo is on course for victory in Indonesia's election, the first unofficial results show, with one count putting him 13 percentage points ahead of his rival.

Pollster CSIS gave Mr Jokowi, as he is universally known, 56.7 per cent with more than half of the vote counted, while the former general Prabowo Subianto lagged behind on 43.3 per cent.

Another count, by the Kompas newspaper, gave Mr Jokowi 55.45 per cent to Mr Prabowo's 44.55 per cent. Indonesia's election body authorises these "quick counts" in lieu of exit polls, with official results taking many days to be confirmed.

Produced by reputable news outlets and survey organisations, the early counts have proved reliable in past elections. Another four organisations also had Mr Jokowi winning by between 7.5 and 11.6 percentage points.

Indonesia voted on Wednesday in one of the most logistically challenging single-day elections ever held. More than 192 million people were eligible to cast their ballots and asked to choose both a president as head of the government and representatives for two national assemblies.

Delivering ballot boxes to Indonesia's hard to reach places Show all 10 1 /10 Delivering ballot boxes to Indonesia's hard to reach places Delivering ballot boxes to Indonesia's hard to reach places Workers transport ballot boxes to Bonto Matinggi village, South Sulawesi AFP/Getty Delivering ballot boxes to Indonesia's hard to reach places Army and police guards guide the delivery of ballot boxes in remote East Java AFP/Getty Delivering ballot boxes to Indonesia's hard to reach places Election officials deliver ballot boxes to a remote village in Southern Aceh AFP/Getty Delivering ballot boxes to Indonesia's hard to reach places Workers deliver ballot boxes to Bandung in West Java amidst heavy flooding AP Delivering ballot boxes to Indonesia's hard to reach places Workers deliver ballot boxes to villages outside the city of Bogor EPA Delivering ballot boxes to Indonesia's hard to reach places Election officials load ballot boxes for delivery to a remote village in Southern Aceh AFP/Getty Delivering ballot boxes to Indonesia's hard to reach places Workers deliver ballot boxes to remote villages in Papua province AFP/Getty Delivering ballot boxes to Indonesia's hard to reach places Workers deliver ballot boxes by boat to remote villages in Papua province AFP/Getty Delivering ballot boxes to Indonesia's hard to reach places Workers load ballot boxes onto a lorry in North Sumatra AP Delivering ballot boxes to Indonesia's hard to reach places Army and police guards guide the delivery of ballot boxes in remote East Java Reuters

The crucial presidential race pitted Mr Jokowi, a former furniture salesman whose victory in 2014 was seen as finally breaking the hold on power of Indonesia’s deeply entrenched military and political elites, against Mr Prabowo, a self-styled strongman who cosied up to the country's powerful hardline Islamist factions in a bid to avoid a repeat of his 2014 failure.

During campaigning, Mr Jokowi highlighted his track record from his five years in power, pointing to major infrastructure developments including ports and toll roads, as well as solid yearly growth of around 5 per cent.

Mr Prabowo ran a fear-based strategy, warning that Indonesia risked being taken over by foreign influences - most likely referring to China - or the breakup of the archipelago nation, without a strong leader at the helm.

Mr Jokowi said the initial results indicated he had won, but called on his supporters to be "patient" and wait for the offiical tally announced by the election commission.

"Indications from exit polls and quick counts, we have seen all, but we must be patient and wait for the KPU's (election commission's) official tabulation," he told a news conference, during which he said the elections had been "honest and fair".

"Let's all reunite as brothers and sisters, after the legislative and presidential election," he said.

Asked to comment on the "quick count" results, Prabowo campaign spokesman Dahnil Anzar Simanjuntak said that numbers based on 50 per cent of votes was not enough.

"We will wait," he said.

A senior government official close to the president said before the election that a win for Mr Jokowi with 52-55 percent of the vote would be a "sweet spot", and enough of a mandate to press on with, and even accelerate, reforms.