The world's third-biggest democracy is set to vote in simultaneous presidential and legislative elections in February next year.

The court will decide on the judicial review requests on Oct. 16, its spokesperson said on Tuesday.

The president's son and mayor of Surakarta city Gibran Rakabuming Raka has not announced any intention to run, but politicians supporting the campaign of leading presidential candidate Prabowo Subianto have called for Gibran to become Prabowo's running mate.

The current minimum age for a presidential and vice presidential candidate is 40. The court has received seven judicial review requests calling for the age limit to be lowered to 35. Gibran is 36.

One of the petitioners, the Indonesian Solidarity Party argued the age limit was discriminatory, according to court minutes. The party is currently chaired by the youngest son of Jokowi, as the president is popularly known.

The court should not have taken the case, arguing the changes requested should have been done by putting a bill to parliament, said Feri Amsari, a constitutional law expert from Andalas University.

"This is unhealthy for our democracy," he said, noting the election process is already underway.

While the court is likely to keep the minimum age unchanged, judges may add a clause that allows anyone with experience working as a senior government official to be nominated, Feri said, adding this will still benefit Gibran if he plans to run.

He also highlighted that the court's chief justice is Jokowi's brother in law.

Candidates are expected to formally register to the elections commission on Oct. 19 to 25.

Prabowo and former Central Java Governor Ganjar Pranowo currently lead in a tight race, with former Jakarta Governor Anies Baswedan trailing behind, according to recent opinion polls.

(Reporting by Ananda Teresia, Editing by Gayatri Suroyo and Sharon Singleton)