Social media users are being warned that they could face legal action if they share hacked nude photos of celebrities.

Apple and the FBI are investigating the breach of the iCloud service, which led to hundreds of explicit photos of Hollywood stars being released online.

One of the victims, Oscar winner Jennifer Lawrence, says "authorities will prosecute anyone who posts the stolen photos online".

A spokesman for Ariana Grande said the photos that claimed to show her are fake and Victoria Justice (21), an actress and singer-songwriter, claims that leaked photos of her are also fake.

The images were posted online by a hacker who claims to have taken them from personal iCloud accounts.

Actress and singer Mary E. Winstead confirmed that the photos of her are real, but were taken privately with her husband years ago.

Twitter is reportedly shutting down any accounts that are disseminating the pictures.

Reports say that the hacker claims to have more photos and videos, and has offered to release more in exchange for money.

Social media analyst Stephen O' Leary told Newstalk Breakfast that internet users could face serious consequences if they circulate the images.