Moscow - A team of experts sent by the World Anti-Doping Agency will meet Russian officials in Moscow on Wednesday to begin the process of recovering data from the era of institutional doping.

On the eve of the opening meeting, WADA had not revealed either the names of the three scientific and technical experts WADA has selected, nor the location of their meeting with the representatives of the Russian authorities.

The face-to-face meeting will prepare the ground for the process, which could take days or even weeks, of extracting doping data from the former Moscow laboratory.

WADA suspended Russian doping agency RUSADA in November 2015, after investigations, including one by Canadian lawyer Richard McLaren, found that, between 2011 and 2015, Russia organised massive doping fraud centred on a Moscow testing laboratory.

WADA made access to the lab a prerequisite of reinstating RUSADA.

After a long stalemate, WADA agreed, in September, to reverse the steps: declaring RUSADA "compliant" before the recovery from Moscow of raw data from drug tests between 2011 and 2015.

Widely criticised for the decision, WADA has promised it will impose new sanctions if Russia does not cooperate by December 31.

Since the start of the Russian affair, international sports bodies have faced the problem of the lack of original data.

In February, the Court for Arbitration in Sport overturned the punishments of 28 of the 43 Russians suspended by the International Olympic Committee for the Winter Games in Pyeongchang for benefitting from state doping at Sochi four years earlier.

"What we need to exonerate an athlete, or to sanction an athlete, is the original screening data, and this is what we will get from the Moscow lab," Guenter Younger, WADA's Director of Intelligence and Investigations, told AFP.

Those screenings, along with the lab database and the McLaren findings, could help build stronger cases.

"In order to complete our cases and to be sure that we have positive cases or not, we need all the data, and then we have a chain of evidence," Younger said.

But, according to several anti-doping sources, the destruction or falsification of the raw data mean the investigation are likely to result in far fewer cases than suggested by McLaren, who estimated that 1,000 athletes, in thirty disciplines, benefited from the system.

"The challenge is for most of them, we don't really have samples, because they were destroyed at that time," said Younger.

"We have only data from the presumptive screenings and additional information that we have from our investigation."

So far, only two federations - athletics (IAAF) and biathlon (IBU) - have instituted disciplinary proceedings based on the McLaren reports. The IAAF, which has suspended Russia from all international competitions since November 2015, except for hand-picked athletes, meets December 3-4 to decide whether to continue the sanctions.