If Selena Gomez wants to ditch her wholesome image as a Disney child and girlfriend of teenaged pop star Justin Bieber, then her raunchy and raucous new film "Spring Breakers" seems as good a place as any to start.

The movie, which premieres at the Venice film festival on Wednesday, is directed by Harmony Korine and stars Gomez and fellow Disney graduate Vanessa Hudgens as bikini-clad revelers on a drink- and drug-fuelled orgy of beach parties and pranks.

The camera zooms in on scantily clad teenagers gyrating to the music, local drug dealers snort cocaine from writhing, topless girls and mobsters cruise the streets of Florida in Lamborghinis in a hedonistic portrait of the "American Dream".

Gomez plays Faith, the least wild of a group of four young college students on their mid-term "spring break", and the actress admitted that some fans would find the movie shocking.

"Obviously I know that coming from Disney Channel gives you kind of a brand in a way," the 20-year-old told reporters in Venice after the movie was screened to the press.

"People do put a label on you. I know that I have younger fans, and this is an opportunity for myself to kind of grow. It is a little shocking, I think, for the younger audiences ... but I think it was right for me.

"I did things I didn't even know I could do on the movie and I do think it was because I trusted Harmony."

U.S. actresses Vanessa Hudgens (L to R), Selena Gomez, Rachel Korine and Ashley Benson pose for the photocall of the movie "Spring breakers" during the 69th Venice Film Festival in Venice September 5, 2012. Photo: Reuters

Gomez, who rose to fame as a teenager on Disney show "Wizards of Waverly Place" and enjoyed success as a pop singer, added that she turned down the opportunity to play one of the more racy characters.

"I just didn't think I was ready for it, and I do think that Faith is right for me at this time in my career and in my life. Of course eventually I'm going to kind of work my way up to that I think," she added.

MIXED REVIEWS

Reaction to the movie in Venice has been mixed.

Korine is described as an "enfant terrible" of American film making who is best known for writing controversial sex movie "Kids" and directing the experimental "Julien Donkey-Boy".

Some critics found Spring Breakers implausible and pretentious, while others described it as "wild" and "compelling" and a breath of fresh air at a film festival dominated by more serious, somber cinema.

U.S. actress Selena Gomez poses for the photocall of the movie "Spring breakers" during the 69th Venice Film Festival in Venice September 5, 2012. Photo: Reuters

Robbie Collin of the Daily Telegraph argued that Korine did not go far enough.

"Beneath its Terry Richardson-esque porn chic surface, Spring Breakers is no racier than a mainstream Hollywood teen comedy, and Korine doesn't seem to know what to do with his film's incredibly timely, potentially dangerous premise," he wrote in a three-star review.

In the film, the four friends join hundreds of others whose sole aim is to get drunk, stoned and naked.

Korine said he was aiming to capture the spirit of young people today who are often misunderstood.

"This idea that there is no soul ... with the new generation is not true, but it's just that the soul has morphed.

(L-R) Cast members Vanessa Hudgens, Selena Gomez, Rachel Korine, Ashley Benson, James Franco and director Harmony Korine pose during the photocall of their movie "Spring Breakers" at the 69th Venice Film Festival in Venice September 5, 2012. Photo: Reuters

"It's about kids that are raised on video games, and raised on YouTube clips and raised as television babies, and so the step from watching to doing is sometimes very, very small."

In the story, things turn sour for Faith and her pals when police bust a party and throw them into jail.

They are bailed out by local drug dealer and rapper Alien, played with exaggerated relish by the Oscar-nominated James Franco, who spots them in court wearing only bikinis and decides to take them under his wing.

Faith feels increasingly uneasy as Alien tries to seduce her, and leaves her friends before they are drawn into an increasingly dangerous cycle of sex, money and violence.

U.S. actress Selena Gomez poses on the red carpet for the movie "Spring Breakers" during the 69th Venice Film Festival in Venice September 5, 2012. Photo: Reuters