JAKARTA (BLOOMBERG) - Indonesian President Jokowi Widodo has won the backing of the nation's biggest political party for a second term in office.

The Indonesian Democratic Party of Struggle (PDI-P), led by former president Megawati Soekarnoputri, endorsed Joko, also known as Jokowi, as its presidential candidate in the elections scheduled for April next year, according to Pramono Anung Wibowo, Cabinet secretary and a member of the party.

Jokowi, the first president to come to power from outside the political elite in 2014, has already been endorsed by at least four other political parties, which are part of his government.

The nominations for the 2019 presidential election must be submitted by Aug 10 ahead of a campaign period that officially kick offs in September.

Jokowi has presided over an economy that regained an investment grade sovereign debt rating and has focused on improving infrastructure in the world's largest archipelago, but has also faced difficulties in parliament and criticism from hardline Islamic groups.

The president's popularity remains high - a December survey by Jakarta-based Saiful Mujani Research and Consulting put his approval rating at 76 per cent - and after a tricky first few months he cemented his hold on parliament, where he has the support of parties holding more than two thirds of seats.