Boxing great Muhammad Ali is being treated in hospital for a respiratory issue, a spokesman for the former heavyweight champion said.

Ali is being treated by doctors as a precaution with the 74-year-old in a fair condition according to spokesman Bob Gunnell.

Mr Gunnell declined to say where Ali is in hospital or when he was admitted.

Ali has battled Parkinson's disease for years.

The statement from the family spokesman revealed Ali will be in care for only a 'brief' time.

Gunnell said: 'Ali, who suffers from Parkinson's disease, is being treated by his team of doctors and is in fair condition.

'A brief hospital stay is expected. At this time, the Muhammad Ali family respectfully requests privacy.'

Ali was last seen in public in April at a Celebrity Fight Night charity event in Arizona, US.

He scheduled to to visit London earlier this year for the opening of his I am the Greatest exhibition at the O2 but was too ill to travel.

In January 2015 he was found in an 'unresponsive state' by guests at his home and taken to hospital.

Ali is generally considered among the greatest heavyweights in the history of the sport.

He remains the only three-time lineal world heavyweight champion having won the title in 1964, 1974, and 1978. Between February 25, 1964 and September 19, 1964 Muhammad Ali reigned as the undisputed heavyweight boxing champion.