Singer Sinead O'connor has fired back at Internet critics who slammed her for cutting short a 2013 North American tour on doctor's orders.

The Irish star was forced to pull out of scheduled concerts in Los Angeles, San Francisco and Ontario, Canada after falling ill and she has been hurt and angered by suggestions she simply flew home because she didn't want to perform the shows.

In a post on her website, the Nothing Compares 2 U singer writes, "Some people, not fans, but trolls have been unreasonably b**ching on my Facebook page about my having cancelled the last leg of my 2013 American Kindness tour.

"Anyone feeling I merely 'didn't wish to perform', may take the matter up with Dr Mark Rafferty at St Vincent's Hospital in Dublin, Ireland, by whom I was advised on November 30 not to sing for one month. His extremely strong insistence was that I had such an acute case of laryngitis that if I were to sing before the end of that time I would permanently lose my voice. Needless to say, it would have been reckless not to act upon his advice."

She adds, "Actual fans are not people who sit upon one's Facebook page b**ching because you followed doctor's orders. Therefore to suggest that I spoke rudely in response to fans is dishonest. I spoke to trolls, who have no business being on anyone's Facebook page and really ought get a life (sic)."