Much was made about the authenticity of the film by director Kathryn Bigelow and screenwriter Mark Boal, who used insider access to tell the sweeping, meticulously detailed story of the decade-long search for Osama bin Laden.

Then last week, Zero Dark Thirty won five Academy Award nominations, including for best picture, and this past weekend, it was No.1 at the domestic box office with a gross of nearly $US25 million ($A23.77 million).

Yet what may be the film's biggest challenge in the pursuit of Oscar glory is playing out from Hollywood to Washington as debate mounts over the film's accuracy in its depiction of torture and whether the movie itself endorses the use of torture.

Politicians are also investigating whether the CIA gave Bigelow and Boal false information as to whether enhanced interrogation tactics led directly to the 2011 capture and killing of the al-Qaeda leader in Pakistan.

The Academy of Motion Picture Arts and Sciences failed to nominate Bigelow for director, and on Sunday night, Zero Dark Thirty received only one Golden Globe Award from the Hollywood Foreign Press Association - for best actress Jessica Chastain's portrayal of a driven CIA operative.

Could congressional scrutiny over such an emotionally charged issue as torture be affecting Zero Dark Thirty's awards momentum? Will the bicoastal backlash ultimately prevent the film from winning the best picture award when the Oscars are presented on February 24? Could the dispute also have a bearing on other top honours to be given in the weeks ahead by producers, writers and directors guilds?

Among those raising questions about the film are Democratic senator Dianne Feinstein and Republican senator John McCain, who wrote a letter to the CIA's acting director, Michael Morell, asking him to share documents showing what the filmmakers were told.

The fact that the subject of torture is so fresh and relevant in this country also complicates matters for the film.

At least one member of the motion picture academy, David Clennon, has said he will not vote for Zero Dark Thirty in any category because of the way it depicts torture.

Fighting back after days of silence, Bigelow responded to the criticism in an article for the Los Angeles Times on Wednesday, in which she said torture was an undeniable part of the hunt for bin Laden.

"Experts disagree sharply on the facts and particulars of the intelligence hunt, and doubtlessly that debate will continue," Bigelow wrote. "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," she continued. "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."

Amy Pascal, the co-chairman of Sony Pictures Entertainment, which distributed the film, has issued her own lengthy statement in support of the film, saying it does not advocate torture and would have been inaccurate without its inclusion.

"This film should be judged free of partisanship. To punish an artist's right of expression is abhorrent," she said.

But Oscar historian Tom O'Neil thinks punishment is exactly what's happening here.

"Kathryn Bigelow paid a price for giving torture such a starring role in this movie," said O'Neil. "Whether that's a reaction to the controversy over its accuracy or it was a reaction to the use of torture at all ... some people are being thrown by that."

Previous films based on real-life stories like The Hurricane and Mississippi Burning, which looked like serious awards contenders when they came out, took hits as disparities arose between what's on screen and what's the truth, O'Neil noted.

"The characters were portrayed heroically, then we find out they weren't that wonderful," he said.

Omer M Mozaffar, a religious studies professor at the University of Chicago and Loyola University Chicago whose teachings include literature and history, wrote about even more detailed inaccuracies in the film on Roger Ebert's website. Mozaffar, who's originally from Pakistan, pointed out that certain supporting players were speaking the wrong language or had the wrong skin colour for the region.

"As an audience member, I trust that what I'm seeing is the truth," he said. "But it's a two-sided coin. If the filmmaker is saying something is the truth, I'd hope that what they're showing is the truth, but audience members must also remember that they're watching a movie."

Glenn Whipp, who covers the awards season for the Los Angeles Times, agrees that Oscar voters may feel a bit squeamish about Zero Dark Thirty at this point and go for something safe like Steven Spielberg's Lincoln or Argo, which won Golden Globes for best motion picture drama and for director Ben Affleck.

"For academy voters, there's two issues here: Some believe the filmmakers fudged the facts. And even if they didn't get it wrong, there's the notion that showing torture and acknowledging its role in the decade-long hunt for bin Laden all but endorses its use. That's going to ding the film's Oscar hopes," Whipp said. "But Hollywood hates Washington grandstanding, and there's a deep-seated belief among academy members that the complaints are coming from people pursuing their own political agendas."

Whipp doesn't think any perceived controversy surrounding the film was a factor in keeping Bigelow out of contention for best director.

"After all, Zero Dark Thirty was still nominated for picture and four other Oscars," he pointed out. "It's more of a case of the directors' branch still being a boys club."

Still, Zero Dark Thirty star Chastain said it takes a beautiful film to create such impassioned conversation.

"Kathryn Bigelow and Mark Boal, what they've done with this film is end it with an unanswered question: 'Where do you want to go?'" Chastain said. "They don't say: 'This is what we've discovered and this is what's right and this is what's wrong.' They say: 'This is what we've discovered. What do you think?' And whenever you leave that opened, it's going to create controversy because it's not answered for you. That's important."

Zero Dark Thirty releases in Australia on January 31.

AP