Indonesians voting in their country's first direct presidential election are expected to vote President Megawati Sukarnoputri out of office in favour of a former general.
Opinion polls show Ms Megawati trailing well behind her former chief security minister, Mr Susilo Bambang Yudhoyono, in the race to take over a country in the front line of the war on terror.
The first of 150 million registered voters to cast ballots were those on the eastern side of the sprawling archipelago, including Ambon, capital of the Moluccas islands, where hundreds have died in clashes between Muslims and Christians.
In the past, a legislative body chose leaders in the nation of 17,000 islands and 220 million people, of whom about 85 per cent are Muslims.
Security was light in Ambon, which has seen deadly Muslim-Christian clashes in the past. Most of the makeshift polling booths were guarded by solitary police officers.
The election follows a troubled transition to democracy since General Suharto quit in 1998, a six-year period marred by political chaos, economic crisis and bomb attacks by Islamic militants.
Opinion surveys show at least a fifth of the electorate is undecided, however. No candidate is tipped to win an outright majority on Monday, setting the stage for a run-off between the top two candidates in September.
Although Mr Yudhoyono is the favourite, opinion polls show a close battle for second spot between Ms Megawati, former military chief General Wiranto and Muslim leader Amien Rais.
Gen Wiranto is the candidate of the Golkar party, the political vehicle of Suharto when he was in power, while Rais is the supreme legislative chief