It took the form of aggression, passive-aggressive behaviour, withholding relevant workplace information so colleagues wouldn't excel, overloading of work and hazing.
There were also 19 complaints of sexual harassment, dating back to 2001, while Dean found "the gender pay gap is real", with people describing an "old boys' club" with unconscious bias and sexist banter.
Weta Digital announced an independent review in September after a 1 NEWS investigation.
Dean found despite improvements, policies and processes were not adequate in safeguarding workers, and HR didn't get enough management support and wasn't trusted by workers.
"The company's culture needs significant improvement, some departments and realms more so than others."
In a statement provided by Weta Digital, Dean said the company "stands in the top league of the world's digital effects companies".
But she added: "The problem with this visual effect adult is, at heart, it remains the teenage start-up that opened its doors all those years ago. This is the backdrop to, and a prime cause of the complaints I investigated during my 11-week review.
"The company's workforce is not toxic, but as my interviews and survey results revealed, there is a problem in pockets of the organization, and it has manifested in these complaints. The company's culture needs considerable improvement, some departments and realms more than others."
She said "turning around the ship" did not have to be a "difficult or lengthy task".
Recommendations to change its culture "can be acted on quickly and will produce immediate results".
That included the introduction of a code of conduct.
Weta Digital chief executive Prem Akkaraju thanked Dean for her review and also acknowledged the cooperation and openess of the company's staff.
"We have learned a great deal from their sharing of their concerns, and we will be working through the implementation of the recommendations in Miriam Dean's report."
The founders of the company Sir Peter Jackson and Dame Fran Walsh also acknowledged the role of the crew.
"You have been an integral part of the ongoing success of WETA DIGITAL and we thank you for contributing to the review. Please be assured we will be working with the other owners and Prem to action the recommendations and build the culture Weta Digital needs to maintain its status as a leader in the industry."