Legendary former world heavyweight champion Muhammad Ali has been hospitalised due to a respiratory problem.

Bob Gunnell, a spokesman for Ali's family, released a statement on Thursday that said the 74-year-old was in a "fair condition". His stay in hospital is expected to be brief.

Ali was diagnosed with Parkinson's disease since 1984 after a boxing career of over 20 years.

He was admitted to hospital in December 2014 and January 2015 for treatment of a urinary tract infection that was initially diagnosed as pneumonia.