Activists at the Media Action Network for Asian Americans (MANAA) blasted Crowe and the film's producers for appearing to "whitewash" the movie's cast as the military-themed romantic comedy stars Bradley Cooper, Emma Stone and Rachel MCAdams.

In a press release issued to the New York Post last week (ends31May15), MANAA representative Guy Aoki stated, "Caucasians only make up 30 per cent of the population (of Hawaii), but from watching this film, you'd think they made up 99 per cent."

Sony Pictures bosses addressed the controversy by coming to Crowe's defence, but now the director has penned an essay to explain his casting reasons, particularly that of Emma Stone as Allison Ng, a character based on a real person, who is one-quarter Hawaiian.

In a message on, he writes, "Thank you so much for all the impassioned comments regarding the casting of the wonderful Emma Stone in the part of Allison Ng. I have heard your words and your disappointment, and I offer you a heart-felt apology to all who felt this was an odd or misguided casting choice.

"As far back as 2007, Captain Allison Ng was written to be a super-proud one-quarter Hawaiian who was frustrated that, by all outward appearances, she looked nothing like one. A half-Chinese father was meant to show the surprising mix of cultures often prevalent in Hawaii. Extremely proud of her unlikely heritage, she feels personally compelled to over-explain every chance she gets. The character was based on a real-life, red-headed local who did just that.

"Whether that story point felt hurtful or humorous has been, of course, the topic of much discussion. However I am so proud that in the same movie, we employed many Asian-American, Native-Hawaiian and Pacific-Islanders, both before and behind the camera... including (politician) Dennis 'Bumpy' Kanahele, and his village, and many other locals who worked closely in our crew and with our script to help ensure authenticity."

He continues, "We were extremely proud to present the island, the locals and the film community with many jobs for over four months. Emma Stone was chief among those who did tireless research, and if any part of her fine characterization has caused consternation and controversy, I am the one to blame.

"I am grateful for the dialogue. And from the many voices, loud and small, I have learned something very inspiring. So many of us are hungry for stories with more racial diversity, more truth in representation, and I am anxious to help tell those stories in the future."