MONTREAL (AFP) - Celine Dion's brother and sister have trashed the offbeat biopic Aline: The Voice Of Love, inspired by the singer's rise from child stardom to queen of soft rock and set to be released in theatres in her native Canada on Friday (Nov 26).

"I don't recognise the language, I don't recognise my family, I don't recognise our roots," Ms Claudette Dion, the Grammy Award winner's sister, told popular Quebec radio show, La Semaine Des 4 Julie, on Tuesday.

She and brother Michel Dion, who appeared as guests on the show, said the "humour misses the mark", several scenes "went too far" and they accused Valerie Lemercier, who directs and stars in the film, of wildly distorting their famous sibling's life and personality.

"My mother never spoke like that to Rene (Celine's husband), and Celine never wanted for anything. We pass for a gang of classless grumps," she commented.

Mr Rene Angelil was Celine Dion's manager from 1981, when she was 12 years old and he was 38, until two years before he died at the age of 73 in 2016. They married in 1994.

Critics at Cannes where the film had its world premier in July were divided over whether this unpretentious account of the Canadian megastar was a "sincere and moving homage" or "so pointless as a film that you can only see it as an extravagant piece of conceptual art".

The film-makers said then that they tweaked the star's name to Aline Dieu to give them some wriggle room over the details of her story, though claimed it hews closely to Dion's real life and songs.

"The film we saw, Claudette and I, is not exactly what we expected," said Mr Dion, who has accompanied Dion on tour for 30 years as a stage manager.

"That's not our life," added Ms Claudette Dion, seated next to him at the studio.

On Sunday, Lemercier revealed to the local television talk show Tout Le Monde En Parle that she had never met Celine Dion, but has become a big fan.

The 57-year-old actress-director said she tried to make the film "touching and funny like her."

"I hope she will see the care we have all taken to pay tribute to her," she said, adding that she hoped "that one day she will see it and that it will please her".

Dion, 53, postponed a new Las Vegas residency in October, saying she has been suffering from "severe and persistent muscle spasms" that have prevented her from rehearsing for the show.