Considered the first key warm-up race for the Tour, a strong performance in the eight-day Dauphine has often led to solid results in July.

Following the positive dope test for last year's Tour winner Floyd Landis, who denies taking banned-substances, and the retirement of seven-times champion Lance Armstrong in 2005, no clear favourite has emerged.

Valverde was tipped as "the possible future of cycling" by Armstrong in 2005, and his Caisse D'Epargne co-leader Pereiro finished on the podium last year.

"For both Alejandro and Oscar, just like for all the Tour favourites, the Dauphine is a crucial test of form," Caisse D'Epargne manager Eusebio Unzue said.

"It's highly unlikely either of them will win, but they have to be in the front group in the mountains, helping shape the race.

"They've spent three days in the Pyrenees training and their condition is improving fast.

"At the Dauphine, they will have to show they are still progressing and able to handle the pressure in race conditions."

Other top riders in France's third biggest stage race include last year's winner Levi Leipheimer of the United States, Kazakh Alexandre Vinokourov, Belgian Tom Boonen and Spaniard Alberto Contador.

The Dauphine starts with a 4.2-km flat prologue in Grenoble. There is a 40-km hilly time trial on stage three on Wednesday and stage four's ascent of the 20.5-km Mont Ventoux before the race heads into the Alps will decide the race.

REUTERS