The sporting world has been rocked after former laboratory head Grigory Rodchenkov alleged a state-run cover up of doping offences in The New York Times.

If proven, the legitimacy of Russia's home Games - where they topped the medals table - would be shattered.

According to The New York Times, at least 15 Russian medal winners from Sochi could have been involved in all, as well as dozens of others.

Whistleblower Vitaly Stepanov, a former employee of the Russian Anti-Doping Agency, had already claimed to American investigatory programme 60 Minutes that four gold medallists from the host nation were on steroids during the Games.

The International Olympic Committee (IOC) today promised "swift and decisive action" and asked WADA to initiate a "fully fledged investigation" into the allegations.

“WADA is fully committed to investigating these additional allegations that were exposed by 60 Minutes and The New York Times; and to publicly reporting its findings,” said WADA President Sir Craig Reedie.

“WADA has tackled this investigative work as a matter of priority for clean sport.

“Today, we are outlining our approach and what can be expected by stakeholders going forward.”

Mathieu Holz, WADA's invesigations manager, will head the inquiry.

The former Major of the French Gendarmerie will form a "multi-disciplinary team of experts" that will include leading independent scientists such as Professor Christiane Ayotte, director of the WADA-accredited laboratory in Montreal.

Holz will report to WADA's director general David Howman and the man who will soon replace him, current chief operating officer Olivier Niggli.

WADA will liaise with all its stakeholders, including International Federations, if any evidence indicates that a disciplinary process would need to be instigated within their respective jurisdiction.

The IOC had asked the Lausanne Anti-Doping Laboratory, where the Sochi samples are stored for ten years, to cooperate with WADA and the Russian Olympic Committee have also been instructed to provide their full assistance. 

Richard Budgett, the IOC's Medical and Scientific Director, has been put at WADA's disposal.

Rodchenkov had claimed that the cheating in Sochi was so effective the operation ran like a "Swiss watch".

This included the development of a "three-drug cocktail" of banned steroids as well as a covert system to replace the urine of affected medal winners.

WADA has written to Rodchenkov - the former head of the Moscow laboratory discredited after the doping scandal in athletics - to request a meeting.

The Russian has fled to Los Angeles where he is working on a film with Bryan Fogel.

Holz has also asked Stepnaov for a copy of a 15-hour Skype conversation between him and Rodchenkov.

Stepanov had previously claimed he had tapes proving his allegations, but has yet to reply to WADA.

Russia has repeatedly denied all claims against them involving Sochi - and believes a witch-hunt is being mounted against them.

Legal action is being considered against Rodchenkov, according to Sports Minister Vitaly Mutko.

Although there is no current suggestion that the Sochi laboratory allegations extended to the Moscow laboratory, WADA will inquire as part of its investigation.