FIFA had denied claims from Rodchenkov's lawyer that the governing body had not made any attempt to contact the former Moscow Laboratory head turned whistleblower.

Jim Walden, the founding member of the Walden Macht & Haran LLP law firm, has repeatedly insisted FIFA had not tried to speak to Rodchenkov regarding his evidence on the involvement of Russian footballers in the nation's doping scheme.

It follows reports that the entire Russian team from the 2014 FIFA World Cup in Brazil were implicated in the McLaren Report and were being investigated.

The organisation has now claimed, however, that they tried to make contact in November with the help of the World Anti-Doping Agency (WADA), but that the attempt proved fruitless as Rodchenkov was unavailable.

FIFA claimed that they would make another attempt once WADA had re-analysed the samples from the database.

WADA have reportedly confirmed Rodchenkov is now free to provide information to FIFA and other governing bodies.

"The fact is that Dr. Rodchenkov has only recently become available to testify in legal proceedings being undertaken by International Federations (IFs), which he was unable to do previously due to restrictions put in place by US law enforcement as a result of an ongoing investigation in the United States," a WADA spokesperson said, according to Agence France-Presse.

"Once Dr. Rodchenkov became available to testify, WADA put a process in place for IFs to make requests for him to testify in proceedings taken in cases against individual athletes."

FIFA have insisted they will contact Rodchenkov in due course.

"As part of its investigations, FIFA also requested the contact information of Prof. Rodchenkov from WADA and Prof. McLaren," a FIFA statement said.

"FIFA asked them to raise certain questions with Prof. Rodchenkov.

"Up until 22 November 2017, FIFA was informed by WADA that Rodchenkov was not available and no contact information was provided.

"In addition, we can confirm that immediately after receiving the WADA letter with new instructions on 22 November FIFA contacted the lawyer designated by WADA.

"In order to ensure a meaningful process, FIFA agreed with the lawyer that before submitting specific questions to Dr Rodchenkov we would wait to see and conduct a first analysis of the new information from the Moscow laboratory provided by WADA.

"This process is currently ongoing and FIFA will contact Dr Rodchenkov through the agreed channel in due course."

FIFA confirmed last month that it received new information from WADA about Russian footballers implicated in a database obtained from the Moscow Laboratory.

Names of around 300 athletes included in the database were passed on to the respective IFs.

FIFA, who promised "appropriate sanctions" against those involved if required, was then contacted by the Russian Football Union (RFU) regarding the database.

The RFU launched their own investigation into the claims last month and insisted they would be willing to help FIFA with their probe.

A spokepserson for the Russian Anti-Doping Agency, which remains non-compliant with the WADA Code, told Russia's state news agency TASS that they would support the RFU investigation.

The doping scandal has led to Vitaly Mutko, banned from the Olympics for life by the IOC, stepping down as head of the Organising Committee for this year's World Cup in Russia.

Mutko has also temporarily stood down as President of the RFU for six months to fight the ban.