Two of Indonesia's three presidential contenders pledged to protect press freedom in the world's third-largest democracy at a weekend event that frontrunner Prabowo Subianto didn't attend.

The event came just days ahead of the Feb 14 poll, and as some Indonesians raise concerns over an erosion of the country's hard-won democratic freedoms. Criticism over political interference has been levelled especially at outgoing President Joko Widodo, who has given tacit support to Prabowo.

In the past, incumbents wrapping up their second term as president have remained neutral.

On the last day of campaigning, ex-Jakarta governor Anies Baswedan and ex-Central Java governor Ganjar Pranowo signed the National Press Council's written declarations to uphold democracy and press freedom.

It was unclear if Prabowo, represented at the Saturday event by the head of his campaign team, signed the declaration. His campaign did not respond to queries on the matter.

Prabowo is projected by some opinion surveys to pip the 50% threshold needed to win the election in a single round.

The former special forces commander, who is making his third run at the presidency, has long faced allegations of rights abuses during his time in the military. He denies the accusations, but critics have questioned Prabowo's commitment to protecting human rights.

Prabowo's campaign chief, Rosan Roeslani, said at the event: "Freedom of the press is something that we absolutely must maintain and improve ... because it is one of the spearheads of our democracy."

Rosan did not explain Prabowo's absence from the event.

Last week, Human Rights Watch said Prabowo did not respond to a questionnaire on key rights issues facing Indonesians, while Anies and Ganjar submitted detailed answers.

"Two of the main political teams have done Indonesian voters a service by sharing their views," said Elaine Pearson, Asia director at Human Rights Watch.

"Indonesian voters need to know (all candidates') positions on many important issues that affect them and the communities in which they live."