President Joko Widodo is barred from a third term
President Joko Widodo is barred from a third term but remains hugely popular. AFP

Joko Widodo has led Indonesia for a nearly a decade pledging to do things differently, but he stands accused of manoeuvring to build his own political dynasty in next month's presidential vote in a country long known for its nepotistic politics.

The incumbent president is barred from a third term but remains hugely popular, with observers saying he is using his influence to install his sons into prominent political positions, moves that have raised eyebrows in the archipelago nation.

His eldest son was named Indonesia's youngest-ever vice presidential candidate last year to run with frontrunner and Defence Minister Prabowo Subianto.

"It is very obvious that this is a political dynasty in the making," said Made Supriatma, a political expert at the Singapore-based ISEAS-Yusof Ishak Institute.

Gibran Rakabuming Raka, the 36-year-old mayor of Surakarta city, became Prabowo's running mate after Widodo's brother-in-law and chief justice Anwar Usman issued a controversial ruling in October lowering the minimum age for candidates.

Widodo's youngest son has also risen to chairman of a political party despite no prior experience.

They have been helped by the approval ratings of Widodo, who rose from humble beginnings to the top political office, with more than three-quarters of Indonesians approving of his rule, according to recent polls.

It has afforded him an outsized sway on the February 14 vote despite criticism he is chipping away at democratic reforms since Southeast Asia's biggest economy emerged from autocracy in the late 1990s.

That sheen has boosted the campaign of Prabowo with a Widodo junior by his side.

The 72-year-old defence chief -- who has lost to Widodo twice -- polled at 45.8 percent in a recent Indikator Politik Indonesia poll, more than 20 points ahead of his nearest rival, former Jakarta governor Anies Baswedan.

More galling for Widodo's Indonesian Democratic Party of Struggle (PDI-P) is that he has not backed its pick -- former Central Java governor Ganjar Pranowo, currently third in the polls.

Yet Widodo has claimed he will remain impartial, supporting all candidates, even though his son is on the cusp of being Indonesia's youngest-ever vice president.

"Just leave it to the people," he said in October.

But his actions have raised fears he is trying to retain his influence in Indonesian politics, already dominated by dynastic elites since the fall of dictator Suharto.

"The signs of heavy interventions are very visible. Jokowi has an interest. If they (Prabowo-Gibran) lose, it will be the end of Jokowi," said Supriatma.

"The only option is to win."

Prabowo himself is the former son-in-law of Suharto, and Megawati Sukarnoputri, the leader of the PDI-P party, is the daughter of Indonesia's first president Sukarno.

After the second presidential debate on January 7 in which Anies attacked Prabowo, accusing him of owning a swathe of land in Borneo near the planned new Indonesian capital Nusantara, due to open next year, Widodo defended his defence minister.

"Attacking a personal matter that has nothing to do with the context of last night's debate, which was international relations, geopolitics, defence," he told reporters.

"I believe it's not very educative for the public and audience."

On Monday, the pair were pictured eating meatball soup together, in a scene described in some Indonesian media reports as a "political manoeuvre".

Claims Widodo is looking to establish a dynasty have done little to dent his popularity, but his former ambassador to Tunisia, Ikrar Nusa Bhakti, says he should have been more patient in working to install his offspring into the race.

"It's such a shame. (Gibran) could be a governor first. If that was the case, I am confident not only Jokowi's legacy would be politically intact but it would not cause political turmoil," he said.

"It's very unfair that certain candidates received the red carpet treatment while the rest must walk on a very difficult path," he added, referring to alleged acts of sabotage against rival campaigns.

Former vice president Jusuf Kalla sarcastically told a talk show in October that this will be "a child-loving" election because of Widodo's son.

"Others might as well do it too. We businessmen also want our children to prosper," he said.

"Unfortunately, there's only one president, so it's difficult. Everybody is competing."