WADA president Craig Reedie said the new claims would "shake the foundation" of athletes trying to stay clean.
German television channel ARD and Britain's Sunday Times newspaper said they had been leaked a database belonging to athletics governing body the International Association of Athletics Federations (IAAF) with details of 12,000 blood tests from 5,000 competitors which revealed "extraordinary" levels of doping.
Reedie said at an International Olympic Committee (IOC) meeting that the numbers involved and the extent of the use of blood doping had shocked him.
Russian and Kenyan athletes featured strongly in the programme aired just three weeks before the start of the world championships in Beijing.
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"WADA is very disturbed by these new allegations that have been raised by ARD which will, once again, shake the foundation of clean athletes worldwide," Reedie said.
The allegations would be quickly passed to an independent commission looking into allegations aired by ARD in December of widespread doping in Russian athletics.
Russia's Sports Minister Vitaly Mutko called the new allegations "nonsense" that were part of a power struggle within the IAAF.
The experts said that 800 athletes in disciplines from 800m to the marathon registered values considered suspicious or highly suspicious.
They also said: -- At least a third of the medal-winners at world championships and Olympics between 2001 and 2012 had given suspicious tests.
"In one event the entire podium was comprised of athletes, who in my opinion had most probably doped at some point in their career," Ashenden told the ARD programme.
-- The tests showed an increasing use of blood transfusions and hard to detect EPO micro-doses to boost red cell count and performances.
The IAAF said only that it was aware of the media reports and stressed that the data was "obtained without consent."
The governing body said it would "reserve the right to take any follow up action necessary to protect the rights of the IAAF and its athletes.