JAKARTA - Presidential candidate for Indonesia Democratic Party - Struggle (PDI-P) Joko Widodo said he's confident his party will win big in Wednesday's polls to elect a new parliament.

"I'm very confident my party will do very well, my party will win very strong. We will have a big majority," he told reporters after casting his vote here.

Asked when talks of coalition will start, the Jakarta governor, popularly known as Jokowi, said: "Perhaps, we start tomorrow morning."

The 52-year-old governor and his wife Iriana turned up early at the polling station to cast their votes.

Earlier on Wednesday, Mr Erico Sotarduga, a deputy secretary-general of the PDI-P, told reporters that the party seeks coalition partners that do not demand "transactional" deals that focus on group interest. Instead, the party's priority is on national interest, he said.

About 6,600 candidates are vying for 560 seats in the national Parliament.

Some 186 million eligible voters have six hours to go to the polls - from 7am to 1pm local time - to choose their representatives at four levels - MPs in the 560-seat national parliament, provincial assembly, district or city assembly, and the 132-seat regional representative council.

They will vote at over 545,000 polling stations across the sprawling archipelago of 17,000 islands, from the highlands of Papua to islands off the coast of Aceh.

Today's vote will also determine which parties will be able to put forth a pair of candidates for the July 9 presidential election.

Parties must obtain at least 20 per cent of the seats in the national Parliament, or 25 per cent of the popular vote.

Today's poll comes after 21 days of vigorous campaigning from parties and candidates, and three cooling-off days, which ended on Tuesday.

Counting will commence at 1.30pm local time on Wednesday, about half an hour after the polls close. Indonesia has three time zones.

Although official final results will not be released until early May, quick count results that give a fairly accurate indicator of how voters lean are expected within the next few hours.