The American was suspended for two years after testing positive for the banned substance nandrolone at the Oslo Golden League meeting last summer.

The 32-year-old husband of sprint star Marion Jones - who won Olympic 100m, 200m and 4x400m gold medals at last year's Olympic Games - has always protested his innocence.

But Hunter has informed his governing body, US Track and Field, that he will not contest the charges that were brought against him by the International Amateur Athletic Federation.

Confirming he will retire from competition, Hunter said that it was a decision he had been considering for some time.

USATF has confirmed the thrower is submitting the appropriate form to activate this process.

Also, in accordance with its rules, USATF has imposed on Hunter the mandatory two-year ban from the sport.

While accepting the ban, Hunter vehemently denies knowingly taking any banned substance and maintains that he is the victim of a contaminated supplement.

Hunter said he had decided not to contest the doping charges brought against him by the IAAF "because if you look at the history of the IAAF and its arbitration, it (his case) is not going to go anywhere.

"They are interested in being right and they will do whatever they have to do to be able to say they were right."

Under IAAF and USATF rules, however, Hunter is responsible for any prohibited substance found within his system regardless of how it got there, and therefore his statement that he did not intend to take a prohibited substance is no defence to failing a doping test.

A USATF statement said: "Because intent is not an element of the charge, USATF neither endorses nor contests Mr Hunter's denial of intent to commit a doping violation."