The preliminary report on the Rena's collision with Astrolabe Reef will be made public at 9.30am Thursday.

The Transport Accident Investigation Commission interim report of its independent inquiry into the grounding of the containership Rena on Astrolabe Reef will set out only the facts of the accident on October 5.

Rena. Photo: LOC.

The 20 page report, which will be available online will not contain analysis of why events happened as they did, or say what could be changed to help prevent a recurrence.

Those matters will be covered in the commission's final inquiry report.

The TAIC inquiry is completely independent of Maritime New Zealand's regulatory action, environmental enforcement action, or financial claims relating to the grounding.

TAIC reports are intended to help improve transport safety rather than to lay blame, and may not be used in criminal or civil proceedings.