Australians are being warned to stay away from a rally in Jakarta later today with reports extremists may use the protest to conduct acts of violence.

The Department of Foreign Affairs and Trade (DFAT) has said the protest in the capital should be avoided and Australians should consider the need to move around the city.

"We advise you to exercise a high degree of caution in Indonesia, including Bali," DFAT said.

The travel advisory also warned related protests could take place in other Indonesian cities.

Security has been tightened in Jakarta, a sprawling city of 10 million, and police have deployed armoured vehicles and armed personnel as the plan stoked religious and ethnic tensions in the world's largest Muslim-majority nation.

Protesters are demanding Jakarta Governor Basuki Tjahaja Purnama be jailed. ( ABC News: Ari Wu )

Jakarta police say they would secure 26 sites across the capital, with 18,000 police and military personnel to be deployed onto the streets.

The protesters are demanding Jakarta's Christian Governor Basuki Tjahaja Purnama, known as Ahok, be jailed for comments he made about the Koran.

Muslim groups have accused Mr Purnama of blasphemy after he said his opponents had deceived voters by attacking him using a verse from the Koran.

Police are investigating the case against the Governor, who has apologised for the remarks.

Indonesian President Joko Widodo and his vice president called for peace as tensions rose ahead of the protest planned by hardline Muslim groups against Mr Purnama, the first ethnic Chinese in the job.

"Everything and everyone should continue to work as normal, schools should run as normal," Mr Widodo said in a joint statement with Vice President Jusuf Kalla.

Mr Kalla added: "The Government will listen to all opinions ... but I believe because the protest will be carried out on Friday, a holy day, protesters will be respectful. That is our hope."

Anti-riot police stand during security preparations ahead of the planned protest. ( Reuters: Iqro Rinaldi )

But some businesses have told employees to stay home on Friday, citing fears that violence could erupt during the rally.

Police said dozens of social media accounts had been found "publishing provocative statements and images" and urging people to take violent action in the name of Islam against Mr Purnama, including calls to kill him.

"We have seen racially and ethnically divisive statements being spread online and there are indications many of them are anti-Chinese," said Jakarta police spokesman Awi Setiyono.

Ethnic Chinese make up just over one percent of Indonesia's 250 million people, who are overwhelmingly Muslim.

Typically, Indonesian Chinese do not enter politics, but Mr Purnama has been a close ally of Mr Widodo for decades.

He was the deputy governor of Jakarta when Mr Widodo was governor and took over when Mr Widodo stepped down in 2014 to contest the presidency.

Reuters/ABC