Reports say the bomber struck after the completion of church services on Sunday in Solo, a town in central Java

A suspected suicide bomber has detonated explosives in a church in Indonesia's central Java, injuring at least 20 people, according to an Indonesian radio station.

The attacker is believed to have died, a local police spokesman told El Shinta radio.

Citing police and witnesses, El Shinta reported that the blast occurred just after the completion of services on Sunday at the Kepunton church in Solo town.

"I can confirm that there was a suicide-bomb attack in Church Bethel Injil at 10:55 [am]," Djihartono, a central Java provincial police spokesman, said in El Shinta radio broadcast on Sunday.

"The body of the dead one, believed to be the suicide bomber, is lying in the main entrance."

Bambang Sumartono, an official at Dr Oen hospital, said that 20 people, including a child, were admitted to hospital, but that many of them were only slightly injured.

The attacker "walked about four metres behind me", Abraham, a churchgoer, told El Shinta.

"I believe he was disguised as a churchgoer."

Indonesia, the world's most populous Muslim nation, has been battling armed groups since 2002 when suspected al-Qaeda-linked men attacked two nightclubs on Bali island, killing 202 people, mostly foreigners.