CSIRO faces a $30 million clean up bill after barrels of radioactive waste at a major facility were found to be "deteriorating rapidly" and possibly leaking.

An inspection found "significant rusting" on many of the 9,725 drums, which are understood to contain radioactive waste and other toxic chemicals.

Much of the radioactive waste was trucked to Woomera from Sydney in the mid 1990s. Credit:Rick Stevens

CSIRO flagged a $29.7 million budget provision for "remediation works" at a remote location in its latest annual report.

Fairfax Media can reveal the work will take place at a CSIRO facility located on Department of Defence land near Woomera, South Australia.