Hamilton signed for Tinkoff in November 2006

Along with last year's winner Ivan Basso, they have been implicated in the Operation Puerto doping scandal which erupted before the 2006 Tour de France.

Hamilton has served a two-year ban for doping at the 2004 Tour of Spain.

His Tinkoff Credit Systems team said the decision was aimed "at relieving pressure created around the Giro."

"The two riders have been suspended until the authorities have sorted the implications of Operation Puerto."

Operation Puerto was launched after last year's police raids in Madrid and Zaragoza discovered quantities of anabolic steroids, blood transfusion equipment and more than 200 bags of blood.

Over 50 professional riders were forced to miss the 2006 Tour de France because of connections to the Spanish probe and investigations are still continuing.

Hamilton, who won gold in the men's individual time trial at the 2004 Athens Olympics, and Jaksche were due to compete in the race starting on Saturday.

Basso, who quit the Discovery Channel team on Tuesday because of the investigation, insists he has never actually cheated but was guilty of attempts at doping.

He now faces a lengthy ban for his part in the scandal, while Rome prosecutors have formally opened a criminal investigation into the allegations against him.

Doping is a criminal offence in Italy and carries a maximum penalty of two years in jail, although prison sentences of a couple of years are routinely suspended for first offenders.