With around 60 percent of sample votes tallied in so-called "quick counts" that have previously proven reliable, two independent pollsters showed Subianto on more than 55 percent of the vote.

Pollster Poltracking showed Subianto at 59.77 percent of the vote in the preliminary count and Cyrus Network-CSIS had him at 58.62 percent.

Securing more than 50 percent of the vote would be enough to avoid a second-round run-off against one of his two election rivals Anies Baswedan or Ganjar Pranowo. Official results are expected next month.

Tens of millions of people voted in the presidential poll, with Subianto the frontrunner for months despite concerns over his human rights record.

The vote across 800,000 polling stations ended at 1:00 pm local time (0600 GMT) in western Indonesia, while some in Jakarta remained open after the capital was inundated by thunderstorms.

The 72-year-old Subianto, accused by NGOs and former bosses of ordering the abduction of democracy activists at the end of dictator Suharto's rule in the 1990s, was scheduled to address supporters at a central Jakarta arena on Wednesday evening.

The "quick counts" by independent pollsters have been used in previous elections by candidates to claim victory.