Christians in Indonesia celebrated Good Friday under heavy security with forces on high alert following a suicide bomb attack at a cathedral last week.

Heavily armed police and military personnel were seen at churches during Easter celebrations across the vast Muslim-majority nation, where Christians form 10 percent of the population.

Indonesia has long struggled with attacks by Islamist militants, and has been on edge since two suicide bombers blew themselves up at a church in Makassar city on Sulawesi island, wounding 20 people.

"The enthusiasm of churchgoers today was still high despite the attack in Makassar," Indonesian Communion of Churches spokesman Philip Situmorang told AFP.

Indonesia has beefed up security at churches over Easter following a suicide bombing at a cathedral last week
Indonesia has beefed up security at churches over Easter following a suicide bombing at a cathedral last week AFP / SONNY TUMBELAKA

"The police coordinated... to provide security at churches."

Authorities alleged the Makassar bombers were members of a pro-Islamic State extremist group.

National Police spokesman Rusdi Hartono said Thursday that police across the country had been ordered to anticipate potential terror attacks against churches during Easter celebrations.

There was another attack on Wednesday when a 25-year-old woman wearing a face veil entered a police complex in downtown Jakarta and opened fire on officers before she was shot dead.

Police described her as a "lone wolf" Islamic State sympathiser.