* Election expected to help presidential candidate Jokowi
* Campaigning notable for lack of policy initiatives
* Islamic party fortunes on the wane
By Kanupriya Kapoor
JAKARTA, April 9 (Reuters) - Pop stars, actors and mechanics - these are just some of the people hoping to become MPs when the world's third largest democracy heads to the polls on Wednesday in a vote that will heavily influence who becomes Indonesia's next president.
Opinion polls predict the opposition Indonesian Democratic Party-Struggle (PDI-P) will dominate, increasing the likelihood that its hugely popular candidate Joko Widodo, widely known as Jokowi, will win the presidency in that election on July 9.
The Indonesian stock market, which is up 15 percent this year, is likely to react positively to a strong PDI-P showing, Trimegah Securities said. It expects a larger share of votes to allow the party to introduce more business certainty under a Jokowi presidency.
Political parties - there are only 12 running compared with 38 in the last election in 2009 - must secure at least 25 percent of the national vote or 20 percent of the 560 seats in parliament to be able to field a candidate in July's ballot.
Voting starts in Indonesia's distant eastern islands and finishes two timezones away in the densely populated west at 0600 GMT. Exit polls should give an idea of the outcome fairly soon afterwards.
Already much of the debate has shifted to who might become the vice-presidential candidate with Jokowi, currently governor of the sprawling Indonesian capital Jakarta but with no experience on the national political stage.
Much of the campaigning has been notable for its lack of policy initiatives to give Southeast Asia's biggest economy a boost. Growth has weakened partly on the fall in prices for commodities on which the resource-rich country still depends, although it is still expected to be a little over 5.0 percent this year.
Rather than policy, the colourful mass rallies offer free merchandise, food and quite often money to those who attend, along with scantily-clad singers and dancers to whip up enthusiasm.
Parties have also tapped into Indonesia's obsession with social media by launching politically-themed apps and online games. Indonesia is home to the world's third-largest number of Facebook and Twitter users.
According to opinion polls, the top parties behind PDI-P are Golkar, which has nominated tycoon Aburizal Bakrie for president, and Gerindra, which hopes to field former general Prabowo Subianto.
The ruling Democratic Party of outgoing President Susilo Bambang Yudhoyono was hit by a series of high-profile graft cases last year, helping push its support to single digits. Yudhoyono is limited by the constitution to two terms.
Islamic parties, which became popular after the fall of former authoritarian ruler Suharto, have also seen their fortunes fade in the world's most populous Muslim nation, hit by corruption scandals and a strong focus on pluralism in mainstream politics. Five Islamic parties are running this time, compared with eight in 2009.
The first of Indonesia's elections kicks off in the same week as the world's biggest democratic exercise gets under way in India.
Indonesia's embrace of democracy in the past 16 years has seen four different presidents and repeated change of the leading party. That is in contrast to neighbours such as Singapore, Malaysia and Vietnam which have been ruled by the same political groups since their independence.
In Southeast Asia, only the Philippines and Thailand, which has faced prolonged instability, have managed such political diversity.
The election, a $1.5 billion logistical feat, will see more than 186 million voters flock to half a million polling stations across the vast Indonesian archipelago, according to the election commission.
Voters, nearly a third of them under 30, will choose between 6,600 candidates vying for national parliament seats. On the same day, elections will be held for 19,007 provincial and district level legislative assembly seats.
Several of the smaller parties, in particular, are relying heavily on soap opera stars and pop singers to try to win over voters.
Most Indonesians view the national parliament as among the country's most corrupt institutions, according to a 2013 Transparency International survey.
It operates, however, within a presidential system where the executive branch has the authority to overrule an often chaotic legislature. (Additional reporting by Anastasia Arvirianty and Jonathan Thatcher; Editing by Jonathan Thatcher and Dean Yates)