The Democratic Party of Struggle (PDI-P), Indonesia's largest opposition party led by former president Megawati, will dominate the national and regional parliamentary elections on April 9, analysts said.

After high-pressure campaigns since March 16, the country's 12 national political parties and three local parties from the Aceh special region have to cease campaign activities starting Sunday, three days before the poll.

More than 6,600 candidates from the country that consists of 17, 000 islands will compete for 560 seats in the Lower House and 132 in the Upper House, while another 16,000 hopefuls are contesting at the provincial and district levels.

Andrinof A Chaniago, a public policy expert from University of Indonesia told Xinhua days ago that PDI-P will be the biggest winner in the election after its hugely popular candidate Jakarta Governor Joko Widodo, locally known as Jokowi, has been confirmed to run for president last month.

According to a prediction by Bambang Suryono, the president of the academic research organization of Nanyang ASEAN Foundation, PDI-P will be ahead with about 28 percent to 30 percent of the vote followed by Golkar, once the parliamentary vehicle of the dictator Soeharto with 18.5 percent.

Bambang told Xinhua recently that Jokowi, many Indonesians call Jakarta's Obama, is almost certain to win the July's presidential election, however, his party has to secure at least 25 percent of the vote in the national and regional parliamentary election or 20 percent of the 560 seats in the Lower House to nominate him for the race.

Andrinof said the outgoing President Susilo Bambang Yudhoyono' s Demokrat party, which hold the most seats in the parliament, are struggling to win votes in the double digits thanks to the corruption scandals which have hit its popularity hard.

Five Muslim-based parties will be stuck to the current positions if their popularity are not decreased, Andrinof said.

Indonesia's 186.5 million registered voters are expected to head to the polls on April 9 for the day-long elections across the country's vast archipelago.