Fullers chief executive Doug Hudson said the company's immediate focus was on supporting the external inquiries before starting its own investigation into why the 27-year-old vessel veered right into the disused Victoria Wharf, opposite its normal Devonport landing point.
Although a loss of steering power was blamed for an incident in which the Kea gouged a hole in another of the company's ferries tied up at Auckland's Downtown ferry terminal in 2006, he said the cause of Tuesday's crash "could be anything".
"I'm just speculating - it could be a problem with the propeller drive - it could be any number of things."
Mr Hudson acknowledged the Kea was a complicated vessel to steer, giving that it had a propeller at each end, but said the master was a capable and experienced seafarer with an unblemished record.
"There was some criticism the crew didn't do enough at the time [in responding to the crash], but one was injured as well," he said.
"Of the three crew, the master and deckhand were fully involved in trying to assess the situation, damage to the vessel, and get it alongside the wharf and the third person was knocked around herself."
Although he acknowledged several rows of seats moved inside the main cabin, he disputed a passenger's suggestion that they were sent "flying" by the crash.
Part of the reason they were not bolted to the floor was to make room for bikes and prams when required, but they were joined together in their rows.
All those on the upper deck were bolted down.
His company had spent about $1 million last year installing new engines and water tanks in the Kea's hull, and planned an interior refurbishment programme over the next two years when all seats may be bolted down, depending on the investigators' recommendation.