JAKARTA - Indonesia President Joko Widodo on Thursday (Aug 9) picked cleric Ma'ruf Amin as his running mate for next year's presidential elections, in a surprising move that is seen as an attempt to bolster his Islamic credentials.

Mr Ma'ruf Amin, 75, chairman of the Indonesia Ulema Council (MUI), will run as the vice-presidential candidate in the April 17 polls, where Mr Joko is set to face former general Prabowo Subianto in an election to lead South-east Asia's biggest economy.

Mr Joko made his decision after meeting leaders of his nine coalition parties.

He said his decision followed deep contemplation and suggestions from various groups as well as approval from party leaders.

"Maybe there are questions from the people all over Indonesia why Professor Dr Ma'ruf Amin was chosen. Because he is a wise religious figure," said Mr Joko. "We complement each other, representing nationalist and religious figures," he said.

Mr Joko's decision ended months of speculation about who would be his V-P candidate. Just hours before the announcement, there was heavy speculation that the president would pick former Constitutional Court chief Mahfud MD.

Apart from his key role in MUI, Mr Ma'ruf is the supreme leader of Indonesia's largest Islamic organisation Nahdlatul Ulama and has a track record as a regional legislator and lawmaker. He was a member of the People's Consultative Assembly, or MPR, and the Presidential Advisory Board.

He is a graduate of Bogor-based Ibnu Khaldun University,

However, Mr Ma'ruf and MUI have also played other roles in politics that are not without controversy.

One example quoted by his critics is the MUI statement that condemned former Jakarta governor Basuki Tjahaja Purnama - an ethnic Chinese Christian who was an ally of Mr Joko - as a blasphemer for insulting Islam's holy book the Quran in the Jakarta gubernatorial election last year.

Mr Ma'ruf later testified in Basuki's trial.

The Islamic cleric began to weave a closer relationship with Mr Joko after the massive demonstration against Mr Basuki in early November last year, according to local media reports.

There are worries in Indonesia that the tensions seen in the Jakarta election last year, which was marred by the fanning of racial and religious issues largely incited by hardline groups, will be repeated at the 2019 presidential race, which could threaten the re-election of Mr Joko.

Analysts have said that Mr Joko may need a strong Islamic figure as a running mate not only to counter his rivals who may use these religious issues, but also to lure voters in conservative strongholds in Indonesia's most-populated island of Java.

In 2014 election campaign that Mr Joko eventually won, he was hit by an online smear campaign that his family was communist and he is of Chinese descent.

With the announcement by Mr Joko's camp, all eyes are now on his contender, Mr Prabowo, who has yet to make public his choice of running mate.

Candidates for the presidency and vice-presidency must submit their nomination by Friday (Aug 10).

Following the announcment by Mr Joko's camp, Mr Prabowo declared late at night that he will pair with Jakarta deputy governor, Mr Sandiaga Uno.

"Just now party leaders from the Prosperous Justice Party (PKS), the National Mandate Party (PAN) and Gerindra decided and put their trust on me, Prabowo Subianto, and Sandiaga Salahuddin Uno to proceed as the candidates of president and vice-president of the Republic of Indonesia for the 2019 to 2024 period," he said.

Mr Sandiaga, a 47-year old tycoon, defeated Agus Harimurti Yudhoyono, the son of Democratic Party patron and former president Susilo Bambang Yudhoyono, who has lobbied Mr Prabowo's Gerindra party intensively in the past few weeks.

A member of Gerindra, led by Mr Prabowo, Mr Sandiaga is a renowned figure in Indonesia's business circles with his leadership role in Indonesia Chamber of Commerce and Industry, among others. He was ranked as the 47th richest individual in Indonesia by Forbes magazine in 2013.

A senior Gerindra party official said Jakarta's deputy governor Sandiaga Uno is "99 per cent" certain to become Mr Prabowo's pick, Reuters reported on Thursday.

Mr Arya Fernandes, a political analyst from the Centre for Strategic and International Studies, told The Straits Times that Mr Joko's decision on Mr Ma'ruf reveals his willingness to accommodate interests of various political parties and compromise.

However, the move closes the possibility of the establishment of the third axis in the next polls, he added.

Mr Arya further said that after solving the Muslim vote issue, the equally-tough challenge will emerge if Mr Prabowo chose Mr Sandiaga, who represents a young leader, as youth voters might be attracted to the Prabowo-Sandiaga pair.