Amy, which documents Winehouse's life and drug addiction, is set to debut at the Cannes Film Festival in France in May (15) before it hits cinemas in the U.K. in July (15), just three weeks before the fourth anniversary of her death.

However, her dad Mitch Winehouse is not happy with the finished cut of the project because he is convinced filmmakers edited the documentary to portray her family in a negative light.

He claims he approached his lawyers about trying to block the movie's release, but has since decided to sue after its big premiere.

He tells Britain's Sun on Sunday newspaper, "I felt sick when I watched it for the first time. Amy would be furious. This is not what she would have wanted... We can't stop it (the release) but when the film does come out we can sue for libel or slander... Our lawyers will be viewing the documentary and reserve the right to do that and see whether there are any grounds.

"I am painted in it as being an absent father during her last years. It gives the impression the family weren't (sic) there... I was there for her - we were all there every day and Amy phoned me up to seven times a day. From this film there's no impression of that whatsoever."

A representative for the film has responded to Mitch's claims by stating: "We came on board with the full backing of the Winehouse family and we approached the project with total objectivity... We conducted in the region of 100 interviews with people that knew Amy. The story that the film tells is a reflection of our findings from these interviews."

Winehouse died from alcohol poisoning in 2011, aged 27.

The Cannes Film Festival runs from 13 to 24 May (15).