An Indonesian cathedral was rocked by a suspected suicide bombing on Sunday with body parts littering the chaotic scene as Christians inside celebrated the start of Holy Week, police said.

The powerful blast at the church in Makassar city on Sulawesi island happened around 10:30 am local time (0330 GMT) and left at least one person dead and nine church officials and congregants injured, according to authorities.

It was not immediately clear if any of the injuries were life-threatening.

"We suspect it was a suicide bombing," South Sulawesi police chief Merdisyam, who like many Indonesians goes by one name, told reporters.

"We're now trying to confirm his identity," he added, referring to the suspected attacker.

A church security guard tried to prevent a man on a motorbike from entering the compound when the blast occurred, with images from the scene showing what appeared to be a body lying inside the parking lot.

Churches have been targeted in the past by extremists in Indonesia, the world's biggest Muslim-majority nation.

In 2018, a dozen people were killed when a family of suicide bombers blew themselves up at churches during Sunday services in Indonesia's second-biggest city Surabaya.

The family -- including two daughters, aged nine and 12 --  and another family of five, which carried out the suicide bombing of a police headquarters, all belonged to the same Koran study group and were linked to local extremist network Jamaah Ansharut Daulah (JAD), which has pledged allegiance to Islamic State.

Earlier Sunday, Makassar Mayor Mohammad Ramdhan said: "There are many body parts here at the church compound as well as in the street."

News footage showed cars near the building were damaged as police cordoned off the area following the explosion.

The explosion at the city's main Catholic cathedral happened just after congregants finished celebrating Palm Sunday, the first day of Holy Week, which commemorates Jesus's entry into Jerusalem.

It comes a week before Easter.

"We were finishing the service and people were going home when it happened," a man identified as the church's pastor told local media.

An eyewitness at the scene described the explosion as "very strong".