The World War II film stars Andrew Garfield as real-life pacifist Desmond Doss and features a number of bloody battle scenes, particularly those set in Okinawa, Japan.

Actor-turned-director Gibson has faced some criticism for the level of violence shown onscreen, but he insists it works for the movie and was designed to give younger generations a real sense of the horrors veterans face at war.

"It is graphic, but I felt that needed to show that and just show everybody what our veterans go through," he explained on U.S. breakfast show Good Morning America.

Gibson also hopes the film, which has already generated early Oscars buzz, will serve to inspire lawmakers to reconsider the way veterans are treated after returning from places of conflict.

"I think it (the film violence) gives empathy because a lot of people can't understand what these guys are suffering from, particularly today, there's a lot of PTSD," he continued. "There's a lot of guys dropping the hammer on themselves, and it's a serious problem and we need to pay more attention to it and I hope the film can focus on that. If it can bring attention to that, that's good."

Meanwhile, Gibson reveals he really enjoyed shooting Hacksaw Ridge with his star-studded cast, and insists fans will see a different side of Vince Vaughn, who is more known for his comedy roles than his dramatic acting.

"These guys are professionals, they are so good at what they do," Gibson remarked. "This is not Wedding Crashers Vince; Vince is always gonna be intrinsically funny, but he's fantastic."

And the Braveheart star also has high praise for British actor Garfield, who he would love to recruit for all of his future projects: "Andrew inhabits the character perfectly and he did such a good job, I'm really proud of him," he gushed. "I'd like to work with this guy all the time; he's amazing."

Hacksaw Ridge also features Sam Worthington, Hugo Weaving, Rachel Griffiths, Teresa Palmer, and Gibson's own son, Milo. It opens in theatres later this week (ends04Nov16).