The incumbent Governor of Jakarta, who is from the Christian minority, is expected to go through to the next round of voting, according to unofficial election counts.

Key points: No one candidate won more than 50 per cent of votes, meaning a run-off election likely to be held on April 19

No one candidate won more than 50 per cent of votes, meaning a run-off election likely to be held on April 19 Agus Yudhoyono, the son of a high-profile former president, appears to have gained only 20 per cent of votes

Agus Yudhoyono, the son of a high-profile former president, appears to have gained only 20 per cent of votes Christian Governor Ahok is in the lead but still faces trial on blasphemy charges

The so-called "quick counts" carried out by various research companies and media organisations have Governor Basuki Tjahaja Purnama — known as Ahok — leading with 40–43 per cent of the vote.

To win in one round he would have needed more than 50 per cent.

The official count will not be known until the end of this month, but historically the "quick counts" have been accurate.

A record 80 per cent of voters turned out to exercise their democratic right, with police reporting that polling day was peaceful.

Former education minister Anies Baswedan came in second, according to the unofficial figures, and gained about 39 per cent of the vote to be about 3 per cent behind his rival.

Mr Baswedan successfully courted the conservative vote, leaving Agus Yudhoyono, the son of the former president, well behind in the poll, gaining no more than 20 per cent.

Agus Yudhoyono's campaign derailed in the last weeks of the campaign, leaving his father Susilo Bambang Yudhoyono left to answer questions raised about corruption allegations.

Electoral workers at a Jakarta polling station ahead of the election for governor. ( AP: Achmad Ibrahim )

Ahok, meanwhile, is still facing trial on blasphemy charges that carry a sentence of up to five years in prison.

He managed to lead the bitterly fought campaign despite mass protests against him, during which hard-line Muslim groups called for the Christian leader's immediate jailing.

Sorry, this video has expired Jakarta's incumbent governor leading the polls ( Beverley O'Connor )

One protest in November last year turned violent with hundreds injured and one man killed.

The groups, led by the firebrand Islamic Defenders Front, also argued that the Koran forbade Muslims from voting for a Christian leader.

The trial against Ahok and the divisive election campaign are seen as a test for moderate Islam in the majority-Muslim nation.

President Joko Widodo was elevated from the governor's position to top office, so it is seen as one of the nation's most powerful political positions.

In an interview with ABC's 7.30 last year, Ahok said his aim was to one day become the first Christian president of Indonesia.