She denied accusations her film was implicitly endorsing torture by depicting it as an effective means of gaining information.
"Those of us who work in the arts know that depiction is not endorsement. If it was, no artist would be able to paint inhumane practices, no author could write about them, and no filmmaker could delve into the thorny subjects of our time."
Bigelow said it would be illogical to make a case against torture by denying its role in US counter-terrorism efforts.
"Experts disagree sharply on the facts and particulars of the intelligence hunt, and doubtlessly that debate will continue. As for what I personally believe, which has been the subject of inquiries, accusations and speculation, I think Osama bin Laden was found due to ingenious detective work. Torture was, however, as we all know, employed in the early years of the hunt. That doesn't mean it was the key to finding Bin Laden. It means it is a part of the story we couldn't ignore. War, obviously, isn't pretty, and we were not interested in portraying this military action as free of moral consequences."
Bigelow was controversially omitted from the best director category at the Oscars when nominations were announced last week.
Academy of Motion Picture Arts and Sciences member David Clennon has said he would not vote for the movie because it did not acknowledge torture was immoral and criminal.
He said actor Martin Sheen and others were joining his boycott.
Sony President Amy Pascal said it was "outrageous" for an Academy member to try to influence Oscar voting.
"Zero Dark Thirty does not advocate torture. To not include that part of history would have been irresponsible and inaccurate," she tweeted.
- Herald Online