New Zealand's Trade Union Council has accused the government of misleading the public about a dispute between actors and producers on the set of The Hobbit.
In October 2010, after an actor boycott of the film, the New Zealand government changed the law so film industry workers would be contractors, not employees with more rights.
The government said the changes, as well as extra financial incentives for Warner Brothers, were needed to ensure the Hobbit trilogy was made in New Zealand.
The Council of Trade Unions disputes this, saying correspondence released under the Official Information Act shows a government minister publicly overplayed the threat posed by the industrial action, even after the boycott had been lifted.
The documents also reveal that Crown Law advised the government not to change labour laws.
Director of the trilogy, Peter Jackson, came under fire last year when People for Ethical Treatment of Animals said that animals had been mistreated during filming of The Hobbit: An Unexpected Journey.
Mr Jackson denied these claims, saying extraordinary measures had been taken to ensure animals were well-treated.