NZ First is demanding Warner Bros repay $67 million in tax subsidies since The Hobbit's earnings topped $1 billion, saying there's no evidence the films created as many jobs as the government claims.
The first film in the Hobbit trilogy, An Unexpected Journey, is reported to have topped $US886.1m ($NZ1.05b) worldwide since opening in New Zealand on December 12.
Warner Bros received an extra subsidy of up to $US15 million per movie from the government in late 2010, and labour laws were also changed amid a dispute that could have seen the films moved offshore.
Prime Minister John Key says the films have "created" an extra 3000 jobs - but NZ First says that number has been plucked out of thin air.
Documents released to the party under the Official Information Act show an adviser in Mr Key's office contacted Sir Peter Jackson's film company, Wingnut Films, in 2011 asking for the total number of people who would work on the films, suggesting perhaps 3000.
A Wingnut employee replied, saying "3000 is a good number".
"We have 1000 on payroll at the studio, 1000 at Weta Digital and nearing 1000 across Weta Workshop, Park Road Post, related companies and casual contractors," they wrote, adding there would also be a boost to small town economies.
NZ First leader Winston Peters says that response doesn't support the government's job creation claims.
"Questions have to be answered about how many of these jobs existed prior to filming, how many of them will exist once the final film has premiered, and how many of these jobs actually went to New Zealanders," he said.
"There is no doubt now that the deal with the movie industry was more about lining pockets than creating jobs."
Mr Peters also questioned why "film industry fat cats" deserve massive tax breaks while the government won't support the floundering local manufacturing industry.