Davitamon-Lotto’s Australian sprint ace Robbie McEwen, winner of three stages of this year's Giro d’Italia, announced Friday that he was quitting the race after the day's 12th stage.

"I'm going home," said McEwen, who is wearing the points leader's jersey. "The plains are behind us now. I'm sorry to leave but after the Giro I've still got the Tour de France and the world championship. To race everything would be too much. It's a big and beautiful Giro. Goodbye to the tifosi!"

During his three previous appearances in the Giro McEwen, 32, also quit before the mountain stages. With McEwen’s withdrawal, the Maglia ciclamino goes to reigning Olympic champion Paolo Bettini (QuickStep), who had trailed the Australian by seven points in the sprint competition.

This year McEwen achieved his best Giro performance with three stage wins - Santa Maria del Cedro (Stage 2), Marina di Grosseto (Stage 6) and Rossano Veneto (Stage 10). He has won eight Giro stages since 2002. McEwen had hoped for a fourth win on Friday's 178-kilometer 12 stage, but had no intention of riding Saturday's tough stage over the feared Stelvio pass.

McEwen's success in this year's race, however, has been somewhat overshadowed by the Italian anti-drugs squad launching an operation into his Davitamon team, confiscating a hypobaric tent which recreates a high-altitude environment and contravenes Italian law.

Hypobaric tents are often used by endurance sportsmen as they simulate conditions where less oxygen is available and aid the formation of red blood cells in the body.

McEwen said after his Rossano Veneto win that the tent was used not by him but by a rider from his team. And the 32-year-old Belgium-based Aussie maintained likewise when his departure from the race was delayed by over an hour and a half because of police questioning.

"I'm not worried about it," McEwen, who is leaving the race as planned before it heads into some serious mountain climbing over the weekend, said afterwards.

McEwen, the Australian champion, said he had been delayed for so long because he had asked for a translation of some documents the officers had shown him.

"The police wanted to ask me some questions after what I'd said on Thursday," added McEwen, who was quick to underline that his departure was not linked to the incident.