STOCKHOLM (Reuters) - Canadian Nobel Prize winning author Alice Munro will be unable to attend the Stockholm awards ceremony in December because of ill health, the head of the Swedish Academy said on Friday.

Short story writer Munro, 82, revealed in 2009 that she had undergone coronary bypass surgery and had had cancer treatment. She announced this year she had decided to retire from writing.

"Her health is simply not good enough," Academy head Peter Englund said in a blog post, without giving details. "All involved, including Mrs Munro herself, regret this."

The Swedish Academy described Munro as the "master of the contemporary short story" when it awarded her the Nobel prize earlier this month, likening her work to that of 19-century Russian author Anton Chehkov.