Voting began on Wednesday in Indonesia's presidential, national and provincial elections at more than 800,000 polling stations across the country, with nearly 205 million people eligible to cast their ballot.

Voters started entering polling stations at 7am local time in the easternmost province of Papua in an election Defence Minister Prabowo Subianto is favoured to win against two former governors to lead the world's third-largest democracy.

Nearly 259,000 candidates are contesting 20,600 posts across the archipelago of 17,000 islands in the world's biggest single-day election, but all eyes are on the presidency and the fate of Widodo's ambitious agenda after a decade in charge of one of Asia's biggest and fastest-growing major economies.

The race pits two charismatic former governors, Ganjar Pranowo and Anies Baswedan, against controversial frontrunner Prabowo Subianto, a former special forces commander feared in the 1990s as a top lieutenant of Indonesia's late strongman ruler Suharto.

Defence Minister Prabowo is contesting his third election after twice losing to Widodo, better known as Jokowi, who is tacitly backing and betting on his former rival as a continuity candidate to preserve his legacy, including a role for his son as Prabowo's running mate.

Jokowi, who cannot run again, has not explicitly backed a candidate but his implied endorsement is rubbing off on Prabowo, who during the campaign has led all of Indonesia's most watched opinion polls, with two surveys last week projecting he will win the majority of votes and avoid a second round.

Those surveys show Prabowo with 51.8 percent and 51.9 percent support, with Anies and Ganjar a whopping 27 and 31 points adrift respectively. To win outright, a candidate needs over 50 percent of votes and to secure 20 percent of the ballot in half of the country's provinces.

"Jokowi as the decisive factor has been proven by the rising popularity of Prabowo," said Arya Fernandes of Indonesia's Centre for Strategic and International Studies.

"But whether or not Prabowo can win in one round, there are some other factors outside of Jokowi," he said, noting turnout would be crucial for Prabowo.

"Jokowi's effect has reached the maximum level." (AFP/Reuters)