A crowd holding a a mask with a cartoon image of Indonesian President Joko Widodo at a political rally in Jakarta, Indonesia. Ed Wray | Getty Images

Indonesia — Southeast Asia's most populous country — is due to hold elections this week, and some 193 million voters are expected to cast their votes for five levels of public office in a single day. The April 17 polls will see millions of voters cast their ballots at more than 800,000 polling stations across the archipelago — an exercise described by some analysts as the world's largest single-day elections. "The scale of Indonesia's electoral process is mind-boggling, with five separate elections at once," said Ben Bland, director of the Southeast Asia project at Australian think tank Lowy Institute. "By contrast, India, which is the world's biggest democracy, is conducting its parliamentary elections through a rolling regional process over six weeks in April and May," Bland wrote in a report posted on the think tank's website. India kicked off its month-long political contest last Thursday. The South Asian nation is the second most populous country in the world with a population of around 1.31 billion, according to the U.S. Census Bureau. Meanwhile, Indonesia ranks fourth globally with 264.9 million people spreading across 17,000 islands, U.S. Census Bureau data showed.

What to expect

Indonesian voters will cast five ballots to select the following office-holders: President and vice president

575 members of the People's Representative Council, or Indonesia's house of representatives

136 members of the Regional Representative Council, or the senate

More than 2,000 seats in provincial legislatures

Around 18,000 seats in district and city councils The presidential race has dominated media coverage and public discussions. Incumbent President Joko Widodo — popularly known as Jokowi — is expected to repeat his victory over Prabowo Subianto, according to opinion polls. The two candidates ran against each other in the 2014 presidential race.

An equally important event to watch is the contest for the People's Representative Council — or the house of representatives, said Achmad Sukarsono, the lead analyst for Indonesia at risk consultancy Control Risks. The chamber has been dominated by a coalition led by the Indonesian Democratic Party of Struggle, or the PDIP — the political party backing Jokowi's presidential bid. But the coalition's presence in parliament could slip to a slim majority, predicted Sukarsono. He explained that seats in the chamber are allocated based on a complicated formula, and corruption scandals surrounding an ally of PDIP could give the opposition camp an opportunity to increase its presence in parliament. "We expect the next parliament to be more fractured," the analyst said. "All these point to a more convoluted and disputed parliamentary process, and consequently a president with a diminished ability to enact his agenda." After voting ends, approved pollsters are expected to release "quick counts" or a preliminary outcome of the elections. Official results will likely be known a few weeks later.

What investors are watching

Jokowi winning a second-term in office is the most favorable outcome for financial markets, said Jason Daw, head of emerging markets strategy at French banking giant Societe Generale. "Investors are comfortable with Jokowi's policies and governing style," Daw told CNBC in an email. "A surprise win by Prabowo could jolt investor sentiment." Foreign investors poured into the Indonesian stock market in the first two months of 2019. They bought a net 10.47 trillion rupiah ($740.18 million) worth of shares in January and February this year, according to the country's stock exchange.