The last Japanese citizen to be evacuated from a war-torn region of Papua New Guinea has returned to witness a long-awaited referendum on independence.

Satoru Kutsukake first arrived in Bougainville in May 1987 as an idealistic 28-year-old as part of the Japan Overseas Cooperation Volunteers, the Japanese version of the Peace Corps.

But just over a year after his arrival, the region was engaged in the bloodiest conflict in the Pacific since World War II, fought largely between the secessionist Bougainville Revolutionary Army and the Papua New Guinea defense force.