Indonesia's largest opposition party Gerindra will officially nominate former army general Prabowo Subianto as its candidate for the 2019 presidential polls.

Gerindra, which is short for the Great Indonesia Movement, also hopes to unveil Mr Prabowo's running-mate at the announcement set for April 11, said party secretary-general Ahmad Muzani.

Mr Muzani was speaking to reporters on Monday (Mar 26) night, following a flurry of public comments by several Gerindra politicians in recent days calling for the party to nominate Mr Prabowo for the elections.

Jakarta governor Anies Baswedan, who Mr Prabowo backed during the gubernatorial elections last year, has been tipped to be Gerindra's vice-presidency candidate.

However, Mr Muzani said no decision has been made yet, adding that "Mr Prabowo has suggested that we be patient in this matter".

The April 11 announcement should end speculation that the opposition chief may not be running in the next presidential race. For the first time, the nationwide vote on April 17 next year will see Indonesians heading to the polls to choose their president as well as their MPs on the same day.

President Joko Widodo's bid for re-election, which would set up a repeat of the battle with Mr Prabowo, was a foregone conclusion until recently. At the 2014 polls, Mr Joko, 56, beat the 66-year-old Gerindra chairman with 53 per cent of the votes.

But the announcement of Mr Prabowo's nomination took longer than anticipated.

While many observers believe it was a matter of "when, not if" he would run again, there were still questions over whether he had sufficient support for another lengthy and expensive national campaign.

During a recent interview with Bloomberg news, Mr Prabowo's brother, businessman Hashim Djojohadikusumo, tried to dismiss doubts that Gerindra lacks the funds to run a "credible" presidential campaign.

Professor Syamsuddin Haris from the Indonesian Institute of Sciences believes the announcement of Mr Prabowo's nomination may have been delayed because the former commander of Indonesia's special forces may still be looking for a financier to help fund his campaign.

He told The Straits Times on Tuesday: "My reading also is that Prabowo may be looking for a vice-presidential candidate who has the money, or financial backing."

Once the son-in-law of President Suharto, Mr Prabowo is every bit the military man many older Indonesians revere and favour as a political leader.

Mr Prabowo has also managed to reinvent himself from an army officer allegedly linked to human rights abuses into an opposition leader who champions the rights of Muslim conservatives. He is not short on political suitors.

Gerindra vice-chairman Fadli Zon said earlier this month that the party is set to join forces with the Prosperous Justice Party (PKS) to back Mr Prabowo's bid for the presidency.

Former Indonesian armed forces chief Gatot Nurmantyo reportedly met Gerindra officials recently and is currently among its list of some 15 potential V-P candidates.

Also on that list is Mr Anies, who defeated the popular Chinese politician Basuki Tjahaja Purnama, or Ahok, during a divisive election in the capital which ended with Basuki being jailed for blasphemy last year.

The PKS - the only party to have declared its support for Mr Prabowo's candidacy so far - believes Mr Anies can help raise Mr Prabowo's electibility.

But the party still hopes one of its cadres can get on the V-P ticket, said PKS leader Mardani Ali Sera.

Vice President Jusuf Kalla, who suggested Mr Anies as Gerindra's gubernatorial candidate at the time, said on Sunday that while it was not impossible for the latter to contest the 2019 presidential polls, it would be better if he "concentrates on his job as Jakarta governor".

Centre for Strategic and International Studies political analyst Arya Fernandes believes Mr Anies may have other plans.

"Seeing his political track record, I believe his aim is to be number one. I think he will target the next presidential election in 2024 rather than leave his post now," he told The Jakarta Post. "The chance of (him) winning is very low. If he loses, he won't be able to come back as governor."

Jakarta State University's sociopolitical expert Ubedilah Badrun said a key strategy of Mr Prabowo is to wait for his rival to name a running mate before making his move.

There are also suggestions of a possible Joko-Prabowo joint ticket.

"Not surprisingly, Prabowo may also be counting on possibly becoming vice-president to Jokowi, though that is highly unlikely," said Professor Syamsuddin, using the President's popular nickname.

The rumours were also quelled by Mr Fadli, who said it was impossible for such a coalition to be formed.

Mr Joko has yet to name his running-mate for the race, but his recent public appearances has fuelled widespread speculation as to who he may pick.

On Saturday (March 24), he strolled with Golkar party chief chairman and Industry Minister Airlangga Hartarto at the Istana Bogor, where they reportedly discussed the 2019 elections.

The President's decision to wear a yellow t-shirt that day - yellow being the party colour of Golkar - did not go unnoticed.

When asked on Monday during a working visit to Banjarbaru, South Kalimantan, Mr Joko would only say that the choice of his running-mate is being discussed among the various parties in his coalition.

"It's still a long process," he added. "So please do not ask about this matter again."