"Don't be a coward. David, twice you canceled against the Klitschko brothers (last year). But now the time has come," the IBF, IBO and WBO champion, whose brother Vitali holds the WBC crown, said in a video message posted on his website (www.klitschko.de).

"In the name of all boxing fans I officially challenge you to fight me. You cannot keep running away from me. I am ready so what are you waiting for?” the Ukrainian said.

Haye retained his WBA title on April 3 after stopping American John Ruiz in the ninth round.

A Klitschko v Haye fight is the one many fans would like to see given that the two brothers will not fight each other.

Haye pulled out of a scheduled fight with Vladimir last year, citing an injury, although it was more a case of the two sides and their promoters failing to reach a deal.

A Haye-Vitali Klitschko match also failed to materialize although the Briton, with a record of 24-1-0, said after the Ruiz fight he would like to take on either of the Klitschkos.

Vladimir retained his belts with a knockout victory against Eddie Chambers in March while Vitali takes on European champion Albert Sosnowski of Poland for the WBC crown on May 29.