Two leading black figures in film, Steve McQueen and Lupita Nyong'o, have added their voices to the campaign for more diversity among the Oscar nominations.
McQueen, the British director of Oscar-winning film 12 Years A Slave, called for black actors to be given a "fair bite", while Academy Award-winning actress Nyong'o said she stood with her "peers who are calling for change".
The Academy has been subject to criticism and calls for a boycott over its all-white line-up of acting nominees, with its president, Cheryl Boone Isaacs, now pledging "big changes" to bring about "much-needed diversity".
Nyong'o, who won the gong for Best Supporting Actress in 2013 for her role in McQueen's 12 Years A Slave, wrote on Instagram: "I am disappointed by the lack of inclusion in this year's Academy Awards nominations. It has me thinking about unconscious prejudice and what merits prestige in our culture."
She added: "The awards should not dictate the terms of art in our modern society, but rather be a diverse reflection of the best of what our art has to offer today.
"I stand with my peers who are calling for change in expanding the stories that are told and recognition of the people who tell them."
McQueen, who was nominated for the Best Achievement in Directing award for 12 Years A Slave, said: "I think racism has a lot to do with it, but also the whole idea of people not being adventurous enough in thinking outside of the box as such."
He told the BBC: "It can't be about box office, because I think black actors and stories along those lines have done very, very well, obviously.
"So it's about executives in cinema and film studios, television, cable networks, giving those storylines and those actors a fair bite."
Spike Lee and Jada Pinkett Smith have both announced they will not be attending the ceremony.
Lee said he "cannot support" the "lily white" Oscars, while Pinkett Smith said it was time for people of colour to disregard the Academy Awards.
In a video message posted online, she said: "Begging for acknowledgement, or even asking, diminishes dignity and diminishes power. And we are a dignified people and we are powerful."
Selma star David Oyelowo has also spoken out about the diversity problem, which was the subject of an online campaign last year using the hashtag OscarSoWhite.
Speaking at the King Legacy Awards, where he was presenting an award to Boone Isaacs, he said: "The Academy has a problem ... It's a problem that needs to be solved."
He added: "A year ago, I did a film called Selma and, after the Academy Awards, Cheryl invited me to her office to talk about what went wrong then.
"We had a deep and meaningful (conversation). For 20 opportunities to celebrate actors of colour, actresses of colour, to be missed last year is one thing; for that to happen again this year is unforgivable."
Boone Isaacs has responded to the controversy, writing in a statement on Monday: "I am both heartbroken and frustrated about the lack of inclusion. This is a difficult but important conversation, and it's time for big changes.
"The Academy is taking dramatic steps to alter the make-up of our membership. In the coming days and weeks we will conduct a review of our membership recruitment in order to bring about much-needed diversity in our 2016 class and beyond.
"As many of you know, we have implemented changes to diversify our membership in the last four years. But the change is not coming as fast as we would like. We need to do more, and better and more quickly."
British actor David Ajala, known for his roles in Beowulf and Fast & Furious 6, said more diversity in the Oscar nominations was not "a big ask".
London-born Ajala told 5 News: "If there weren't so many successful black actors you could understand ... but we have many black actors not being represented properly.
"If any alien was introduced to Academy Awards, their impression would be it's a white-based society. Women are not represented equally and fairly.
"The best people in these roles should be nominated and there should be a conscious effort to make sure that the Academies are as diverse as possible.
"We should be championing diversity, I don't think it's a big ask."
But the 29-year-old said he would not be taking part in the boycott, explaining: "I don't think not watching the Oscars is going to solve anything."
Prometheus actor Rafe Spall said Idris Elba not being nominated for this year's Oscars was a "notable omission".
He told Good Morning Britain's Susanna Reid and Piers Morgan that the situation was "kind of outrageous".
"Especially the last two years when there has been extraordinary performances by black actors. Idris Elba, this year, I think is a notable omission and the cast of Creed, which is a film that everybody loves," he said.
Spall, who is the son of actor Timothy Spall, said he thought the voting demographic needed to be looked at, adding: "The people that vote for the Oscars, the people who vote for the Baftas, that's the thing that needs to change."