Four asylum seekers from conflict-ridden Syria will soon initiate a lawsuit against the central government to seek official refugee status, the first from their nation to do so, a lawyer said Monday.

The unprecedented move comes amid mounting calls by experts for a root-and-branch overhaul of Japan's notoriously opaque, insular and slow-paced refugee system.

It also reflects simmering frustration among asylum seekers from Syria over Japan's dogged refusal to grant them refugee status.