Fashion designer and former model L'Wren Scott has been found dead in her New York apartment.

The fashion designer's boyfriend, Rolling Stone singer Mick Jagger, was said to be "completely shocked and devastated" by the news.

New York police confirmed that officers found a woman's body after being called to an apartment at 11th Avenue in Manhattan's Chelsea neighbourhood shortly after 10am (2pm Irish time).

"Upon arrival, officers discovered a 49-year-old female unconscious and unresponsive," a police spokeswoman told AFP.

"She was pronounced dead on arrival. The investigation is ongoing. The medical examiners will determine the cause of death."

A spokesman for the New York Fire Department confirmed only that firefighters had found a body when called to the address to respond to a "possible cardiac arrest."

"We cannot release any more information before any proper family notification," the police spokeswoman said.

A law enforcement official described the 49-year-old's death as an apparent suicide.

Mr Jagger is currently in Perth, Australia, where he is touring with the Stones, according to his official Twitter account.

Ms Scott had dated the Rolling Stones frontman since 2001 following his split from wife Jerry Hall.