A DAMNING report that predicted the scale of last year's riots by asylum seekers on Christmas Island but was never shown to the Immigration Minister, Chris Bowen, or his department head has been obtained by the Herald.

Written by Keith Hamburger, the report accurately warned that the best efforts of staff or emergency services to contain unlawful behaviour would be ''severely compromised'' by overcrowding, understaffing and inadequate infrastructure on the island.

Riot shields offloaded onto Christmas Island.

It was sent yesterday to the parliamentary committee that is reviewing the country's immigration detention network. The committee will hand down its findings on Friday.

The report implored the Immigration Department to ''avoid at all costs'' failures that could result in harm to staff, asylum seekers, visitors and members of the public. It said such failures, in the worst case, would have ''serious legal consequences''.