LAUSANNE • Russia's attempt to overturn its four-year ban from international sport got under way in Lausanne on Monday, the latest chapter of a long-running and controversial saga over state-sanctioned doping.

Last December, global anti-doping body Wada declared the Russian Anti-Doping Agency (Rusada) to be non-compliant after being accused of manipulating testing data.

The ban meant the country would miss the re-arranged Tokyo Olympics next year as well as the 2022 Winter Olympics in China and football's 2022 World Cup, although its players can play at the Qatar tournament if they wear neutral uniforms, should they qualify.

A hearing at the Court of Arbitration for Sport (CAS), which opened on Monday and is expected to last until Friday, has already caused division.

Wada had requested that the proceedings be held in public, but following disagreement between all parties, the three CAS judges eventually opened the first session behind closed doors via teleconference.

A decision will only be made public on an undisclosed date.

Russia considers its ban to be legally indefensible. Former Russian prime minister Dmitry Medvedev described the suspension as "chronic anti-Russian hysteria".

The hearing is being billed as a landmark week for Russian sport and global anti-doping efforts.

Wada also has plenty on the line after the United States threatened to pull its annual US$2.7 million (S$3.7 million) financing.

US lawmakers accused it of failing to implement governance reforms and have criticised the handling of the Russian scandal.

Also, the International Olympic Committee (IOC) and sports federations are expecting clear directives from the CAS, eight months before the Tokyo Games.

"Wada has left no stone unturned in preparation for this hearing and we are looking forward to having the opportunity to present our case clearly and fairly to the panel," said Wada president Witold Banka.

"I remain convinced that the Wada executive committee made the right recommendation in this case last December.

"As at every other stage, we are following due process in relation to Rusada's compliance procedure as we continue to deal effectively with this complex matter."

The Russian saga is now uncomfortably into its fifth year. In May 2016, Grigory Rodchenkov, the former head of Moscow's anti-doping laboratory, blew the whistle over state-backed doping at the 2014 Sochi Winter Olympics.

Two months later, barely two weeks before the 2016 Olympics started, Wada called for Russia to be banned from Rio. The IOC, however, stopped short of an outright ban and said individual federations would decide whether to allow Russian athletes to compete.

In 2017, the IOC banned the Russian Olympic Committee from the 2018 Pyeongchang Winter Games, but allowed clean Russian athletes to take part as neutral competitors.

A total of 168 Russians eventually competed. Then, in September 2018, Wada controversially lifted its ban on Rusada, despite not having been granted access to its doping-tainted Moscow laboratory.

Russia finally handed over lab data to Wada in January last year. However, in yet another twist, in September Wada gave Russia three weeks to explain "inconsistencies" in the data.

World Athletics announced it had suspended the process of reinstating Russia's athletics federation and was contemplating expelling the country entirely from the sport due to the doping scandal. Wada then decided to ban Russia for four years over the manipulated data.

AGENCE FRANCE-PRESSE