A rare collection of drawings, sketches and paintings by champion boxer Muhammad Ali has sold at auction for nearly US$1 million.

Some 26 art works went under the hammer at Bonhams auction house in New York.

One of the most anticipated works, Sting Like a Bee, sold for $425,000 more than 10 times its pre-sale estimate.

Ali is hailed as one of the greatest ever athletes, activist and poet, but his artistic talents are less known.