Indonesians have voted in the world's biggest single-day election, with unofficial tallies putting President Joko "Jokowi" Widodo ahead with 55 percent with around 38 percent of votes counted.

Kompas news channel has Jokowi leading with 55.37 percent in the bitterly fought campaign dominated by promises to boost jobs and the economy against a backdrop of growing religious intolerance and the rising influence of political Islam. At least three other counts by private pollsters showed similar margins.

A re-run of the 2014 race, it pit former furniture exporter Jokowi — now the incumbent — against Prabowo Subianto, an army general who served as a special forces commander during the 32 year reign of the dictator Suharto. The campaign, which officially began back in September, saw both candidates vowing to fire up Southeast Asia's biggest economy as well as heightened nationalism and allegations of voter fraud.