Indonesian security forces Wednesday captured a senior member of an Daish-linked militant network once headed by the country's most wanted extremist, police said.

Muhammad Basri, from the Eastern Indonesia Mujahideen, was caught in a joint operation between the police and military in Poso district, on rugged Sulawesi island, while another member of the group was shot dead.

"He was caught on Poso's south coast this morning," police spokesman Boy Rafli Amar told AFP, adding he had been taken to a nearby city.

It came two months after the group's leader and Indonesia's most wanted extremist, Santoso, was shot dead by troops, ending a years-long hunt for the Islamic State (Daish) group supporter.

His death was a major victory for authorities in the world's most populous Muslim-majority country. Santoso and his group were responsible for deadly attacks on domestic security forces and had trained militants from around the archipelago.

Basri had been the deputy leader of the Eastern Indonesia Mujahideen, which has been hiding out in the jungles of Sulawesi for years but now has just a handful of members.

He was seen as a successor to Santoso, although it is not clear if he had officially taken over leadership of the group.

After Indonesia suffered a string of Islamic extremist attacks in the early 2000s, including the 2002 Bali bombings that killed more than 200 people, authorities launched a crackdown that weakened the most dangerous networks.

But Santoso repeatedly evaded attempts to capture or kill him, with the long-haired, gun-toting militant regularly appearing in videos urging extremists to launch attacks.

The picture changed recently, with other Daish-linked cells on the main island of Java considered a greater threat.