UNITED STATES - Former heavyweight boxing champion Muhammad Ali has been admitted to hospital with a mild case of pneumonia.

His spokesman Bob Gunnell said the 72-year-old superstar was being treated by his team of doctors and was in a stable condition at the undisclosed hospital.

Mr Gunnell said Ali's prognosis was good because the pneumonia was caught early and a short hospital stay was expected.

Ali, who has Parkinson's disease, appeared in public in September at a ceremony in his home town of Louisville, Kentucky, for the Muhammad Ali Humanitarian Awards.