A patch of Indonesian jungle that Bre-X Minerals had hailed as the gold find of the century is actually a tampering job "without precedent" in the history of mining anywhere in the world, new tests show.

Bre-X released the information in a statement late last night.

An intensive investigation is expected to begin immediately. Bre-X has hired experts to find out why its own findings were so glowing.

"We share the shock and dismay of our shareholders and others that the gold we thought we had at Busang now appears not to be there," Bre-X president and chief executive David Walsh said in a statement.

"We have spent millions of dollars in the strong belief that a sizable deposit existed and have directed all our efforts towards development of the project."