The Pacific Sun rolled up to 31 degrees, injuring 77 of the more than 2000 people on board the P&O cruise ship bound for Auckland on July 30.
The injuries ranged from cuts and bruises to broken bones, while one passenger had part of a finger amputated.
The report, by British maritime officials, obtained by The Herald on Sunday but not yet shown to passengers, concluded it was "pure good fortune" that no one was more seriously injured or even killed by unsecured equipment and furnishings.
Procedures for securing such furnishings, which included a grand piano, casino gaming machines and tables, brought in after an earlier accident on another ship, were not "sufficiently robust", the report said.
It said the Pacific Sun's captain was placed in a difficult situation by the ship's tight schedule, which had placed the vessel in the worst sea conditions.
The crew were unable to see or monitor abnormal swells of up to 7m in darkness and its stabilisers were inoperative, with one worn out and the other useless at the slow speed of the ship.
The ship's satellite system was also damaged in the accident, while passengers became alarmed after seeing crew wearing lifejackets while they were not, the report said.
