Indonesia on Monday amended the eligibility requirements to run for president and vice president, creating an exception to the minimum age threshold that could pave the way for the incumbent's son to enter the race.

Ruling on petitions to change the criteria, the Indonesian Constitutional Court rejected a motion to drop the minimum age below 40 years old, but narrowly approved an exception for candidates who have previously been elected to public office.

There has been widespread speculation that President Joko Widodo's 36-year-old son and current Surakarta City Mayor Gibran Rakabuming Raka will contest the 2024 presidential race as the running mate to Defence Minister Prabowo Subianto.

Jokowi, as the president is popularly known, last week refuted criticism that he was trying create a political dynasty in the world's third-largest democracy, insisting instead that the choice of leader belongs to the people.

The Constitutional Court is led by the president's brother-in-law, Chief Justice Anwar Usman, fuelling further criticism.

"With this decision, article 169 Letter Q of Law No.7/2017 on general elections will now read as follows: a minimum age of 40 years or having held an elected position through general elections, including regional leaders," Usman said of the court's ruling, which split the bench five in favour and four against.

Ray Rangkuti, a local political analyst, said the court's decision raised red flags about interference.

"Critics have maintained from the start that this judgement appears to favour specific family interests, and it has cast question on the integrity of these constitutional judges," he told AFP.

The court is currently considering multiple petitions concerning presidential eligibility, but so far has only approved the one exemption.