The Italian striker, who is currently playing in Serie A for AC Milan on a season long loan from Liverpool, has been accused of posting the images by a former girlfriend.
The woman is said to be a mother of one and in her 40s, according to The Sun.
Her lawyer Giovanni Tonelli said: "My client has been left severely traumatised. She couldn't believe it when she saw these intimate pictures had been posted online.
"She asked for them to be removed but they were still being shared."
But a source at AC Milan insisted: "Mario denies what this woman is alleging."
Balotelli was previously dating model Fanny Neguesha before the pair split in September of last year.
And she has now began dating 25-year-old West Ham midfielder Cheikhou Kouyate .
Fanny was in the Upton Park crowd to see her new beau score for West Ham in the 4-3 defeat to Bournemouth earlier this season.
She posted an Instagram snap of herself at West Ham's stadium, with the number eight, Kouyate's squad number, hashtagged as part of the caption.
The pair are understood to have met when Fanny was in London for a photoshoot earlier this year.
A source is quoted by The Sun as saying: “Fanny is very keen on Cheikhou. They have a lot in common and when she likes someone she really lets them know.
“Guys must work hard to gain her affections. She is very quiet in real life and it takes a while for people to get to know her.
“She mixes in glamorous circles but certainly doesn’t need a man to pay her bills."