A Wingnut staff member replied that 3000 jobs was "a good number".
The staff member said there were 1000 people on payroll at the studio, 1000 at Weta Digital and almost 1000 across Park Road Post, Weta Workshop and related companies and casual contractors.
The staff member noted "flow-on" effects while 700 people working on the film went on the road for nine weeks, boosting small-town economies in the likes of Matamata, Te Kuiti, Piopio, Ohakune and Twizel.
NZ First leader Winston Peters said the documents showed nobody had any idea how many jobs had been created by the Government's $67 million subsidy to Warner Brothers.
"The Government claims that filming The Hobbit in New Zealand created an extra 3000 jobs and this was value for money to taxpayers, but documents from John Key's office show this figure was plucked out of thin air.
"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 Warner Brothers should repay the subsidy it had received from the Government now the film had grossed more than $1 billion.
The correspondence does not say 3000 jobs had been created - only that 3000 people was "a good number" for those working on the films.
But a spokeswoman for the Prime Minister's office stood by the figure, saying 3000 jobs had been created.
"These are people who were directly working on the Hobbit. If the Hobbit had relocated offshore these jobs would not exist."
The spokeswoman said 3000 jobs was "a minimum" and did not count flow-on jobs created for businesses and communities that supplied and serviced The Hobbit.
"The Hobbit production team took 6750 domestic flights, paid for 93,000 bed nights, and hired 1800 rental cars and 1650 work vehicles.
"The production spent more than $9m on construction materials and $1.5m on local food suppliers."
The spokeswoman cited Statistics NZ figures which showed the local film industry employed 15,500 people in more than 23,000 jobs in the year ending March 2011.
"The Government stands by its commitment to attract and retain the film industry in New Zealand in order to reap these significant economic benefits."