All of the 39 are accused by the International Olympic Committee (IOC) of involvement and complicity in a scheme in which urine samples were illegally tampered with and replaced with fake, clean samples during Sochi 2014.

This resulted in each of the athletes being disqualified from Sochi 2014, with all medals being stripped.

The CAS began hearing their appeals against the IOC Disciplinary Commission’s verdicts in Geneva last week.

Their decision will be made public tomorrow, with the CAS Secretary General Matthieu Reeb set to make a short statement at the Pyeongchang 2018 Main Press Centre at 5pm local time.

CAS will also publish the final decision online at the same time.

The verdict has been billed as the most significant in the history of CAS, who yesterday opened their temporary office in Pyeongchang to deal with cases arising at the Winter Olympics.

The decision will come just eight days before the start of the Winter Olympics.

Grigory Rodchenkov, the former Moscow Laboratory director and the main witness in allegations against the athletes, and Richard McLaren, head of a World Anti-Doping Agency-commissioned investigation, were among those to testify via video or telephone links.

A key part of the Russia’s defence is expected to have involved attempting to disprove the testimony provided by Rodchenkov, the mastermind behind the scheme before fleeing Russia for United States and becoming a whistleblower.

He currently remains in the US and is part of the witness protection programme.

insidethegames understands around 10 to 12 of the case rest entirely on his testimony, which includes a "Duchess List" of athletes supposedly taking banned steroids, rather than on any scientific evidence.

Others are implicated by IOC-commissioned analysis of test tubes from Sochi 2014, which showed scratches indicative of tampering, as well as DNA results and analysis of salt levels in samples.

The IOC has said that it fully backs Rodchenkov's credibility as a witness.

A Russian Investigative Committee supposedly conducting its own probe has claimed to have found evidence disproving the IOC cases.

They claim to have obtained documents relating to the doping samples of 15 of the Russian athletes implicated claiming that they were transported in daytime and legitimately registered rather than transferred in a clandestine nighttime operation, as Rodchenkov and others allege.

Another key question to be ruled upon concerns the IOC attempt to award life bans to those who dope at a Games and therefore violate the Olympic Charter.

If successful, this could set a key legal precedent.

A total of 42 of the 43 Russian athletes banned by the IOC Disciplinary Commission appealed to CAS.

Cases involving biathletes Olga Zaytseva, Olga Vilukhina and Yana Romanova, however, were suspended.

Bobsleigh's Maxim Belugin is the one Russian athlete not to have appealed following his disqualification.

He is believed to have produced a positive test result following reanalysis of his samples, although full details of his case have not been disclosed.

Russia are set to have around 169 compete at Pyeongchang 2018 but will not compete under its own flag and will be known as "Olympic Athletes from Russia" - OAR.

Speed skater Olga Graf yesterday became the first Russian athlete cleared to compete to turn down an invitation in protest at the country being forced to participate as neutrals.