Amy Winehouse pulled out of the Rock en Seine festival outside Paris after falling ill at home, the troubled singer's spokesman said as the furious organisers vowed to sue.

Rock en Seine had to scrap the headline gig at two hours' notice and has now threatened legal action against the 24-year-old. It is the second year in a row that the British soul singer has pulled out of the festival.

"Amy Winehouse was regrettably unable to perform at the Rock en Seine show in Paris, due to illness," her spokesman Chris Goodman said.

"She was taken ill at her house and wasn't able to travel to France for the concert."

Some 25,000 concert-goers were waiting for the singer to appear on stage in Saint-Cloud outside the French capital.

"Amy Winehouse should have arrived on the site early Friday evening. We were told by her agent at 8:00 pm that she wasn't coming," Rock en Seine said in a statement, adding there was "no explanation of the exact reasons for her absence".

Winehouse's next scheduled appearance is at the Bestival festival on the Isle of Wight, off the south coast of England, on September 6.

The Grammy Award-winning star, who is fighting drug and alcohol problems, has suffered a string of health scares since apparently being caught smoking crack cocaine in footage released by The Sun newspaper in January.