Indonesia's main opposition party is set to take the most votes according to early results from Wednesday's parliamentary election.

Unofficial tallies show the Indonesian Democratic Party of Struggle (PDI-P) will receive close to 20 percent of the vote, followed by the Golkar party and the Great Indonesia Movement Party (Gerinda).

More than 200,000 candidates from 12 parties were competing for 20,000 seats in national and regional legislatures.

Parties need 25 percent of the national vote or 20 percent of the seats in parliament to be able to field a candidate on their own. Otherwise a coalition must be formed with one or more parties.

If the results are confirmed, PDI-P will most likely need to partner with another group to allow its star candidate, Jakarta governor Joko Widodo, to run in July's presidential election.

Widodo, known as "Jokowi," is popular for his reputation for transparency and his hands-on approach to governance.

Opinion polls showed President Susilo Bambang Yudhoyono's Democratic Party was not expected to fair well after a string of high-level corruption scandals.

Official results will be announced by May 9. The presidential election is on July 9.

Wednesday's vote marks the fourth time for Indonesians to democratically elect their parliament since the collapse of former leader Suharto's 32-year authoritarian rule.

More than 186 million people were eligible to cast ballots in the vote.