Hollywood hits the Oscars red carpet Sunday for its annual show of glitz and pageantry honoring cinema's finest -- with a broiling row over diversity an awkward guest at the party.

Tinseltown's elite are looking forward to the usual sparkling night of celebration, with survival epic "The Revenant" leading the charge for golden statuettes and a panoply of rivals snapping at its heels.

But controversy over the "whitewashing" of nominations -- there are no ethnic minority nominees in the main acting categories for the second year running -- threatens to steal the limelight.

An audience expected to number several hundred million around the world will be hanging on every word uttered by black comedian and actor Chris Rock, who is hosting despite calls for him to join a boycott.

Insiders say the 51-year-old has completely rewritten his opening monologue in the wake of the scandal, which could prove embarrassing for the Academy's 6,000-plus voting members, overwhelmingly white men.

A man looks at souvenir statues before the 88th Academy Awards in Hollywood, California on February 28, 2016. Photo: AFP

Rock has refrained from weighing in on the controversy on social media but took to Twitter on Friday to post a cryptic image of a television with no signal, alongside the message: "See you Sunday... #blackout #oscars."

Hopes for a more routine, less unpredictable red carpet opening looked promising, with forecasters promising glorious blue skies over Hollywood's Dolby Theatre and a peak of 75 degrees Fahrenheit (24 Celsius) for the 88th Oscars ceremony, which gets going at 5:30 pm (0130 GMT Monday).

'SURPRISES WILL HAPPEN'

If a weather forecast can never be entirely reliable, analysts have predicted with an unusual degree of certainty that Sunday will be a night of long overdue glory for old Hollywood hands who have previously missed out.

Jaws will drop if best actor doesn't go to Leonardo DiCaprio for "The Revenant," 22 years after his first of five acting nominations.

A widely-anticipated best supporting actor Oscar for Sylvester Stallone, who reprises his turn as underdog boxer Rocky Balboa in "Creed," would be one of the stories of the night, almost four decades after his only other nominations for the franchise's original outing, "Rocky."

First-time nominee Brie Larson looks to be a lock for best actress, having dominated the awards season with her performance as a kidnapped mother in "Room."

Oscar nominees in selected categories

Best supporting actress favorite Alicia Vikander ("The Danish Girl") faces tough competition from "Carol" star Rooney Mara, on her second nomination, and previous best actress winner Kate Winslet, acclaimed for her work in "Steve Jobs."

"Spotlight," about child abuse in the Catholic Church, and Wall Street satire "The Big Short" look like safe bets for the original and adapted screenplay honors after being recognized by the Writers Guild.

Alejandro Gonzalez Inarritu's "The Revenant" is the overall frontrunner, with 12 nominations, followed by George Miller's stark action epic "Mad Max: Fury Road" with 10 and Ridley Scott's space adventure "The Martian," with seven.

The Gold Derby website, which aggregates the predictions of the experts, has "The Revenant" in the lead for best film, but analysts are split on whether Inarritu will also pick up best director for the second year in a row following his win for "Birdman."

"I think 'The Revenant' will win best picture and the director will go to Miller," said Hollywood analyst Anne Thompson.

"It would be unlikely that the Academy would reward a genre sequel like 'Fury Road' with best picture, but they have gone with directors like Ang Lee and Alfonso Cuaron for well-mounted spectacles like 'Life of Pi' and 'Gravity.'"

"As many people are saying, this is an unusual year when surprises will happen," she added.