Initial counts of Indonesia's parlaimentary poll has put the opposition Democratic Party of Struggle (PDI-P) ahead, but it is unlikely to get enough seats to independently field a presidential candidate.

The quick count of Wednesday's vote by think-tank CSIS, showed PDI-P had emerged on top with a weaker-than expected 19 percent of the national vote, below the 25 percent threshold needed to put forward its presidential candidate.

That means PDI-P will likely need to partner with at least one other party to allow Jakarta Governor Joko Widodo, widely known as Jokowi, to run in July's presidential election.

The Golkar party came in a close second with 14 percent of the vote, while the Gerindra party followed with 12 percent, said CSIS in a quick count based on 80 percent of votes sampled at 2,000 polling stations.

Indonesia's Islamic political parties surprised with a combined 32 percent of the vote. Analysts had expected they would perform worse than their 29 percent share in the 2009 elections, following a spate of corruption scandals.

The government is expected to formally announce the election results in early May.

The elections are the fourth in Indonesia since the downfall of the three-decade Suharto dictatorship in 1998 and are important because they decide who can run for presidential elections in July.

A party or coalition needs 20 percent of seats in the 560-member house of parliament or 25 percent of the national vote to put field a candidate for the presidency.

About 186 million Indonesians were eligible to vote and choose from 230,000 candidates for 20,000 local and national seats in Wednesday's poll.

Source: Al Jazeera and agencies