GENEVA: Athletics is braced to be rocked on Monday by a damning report into allegations of widespread doping and blackmail in a sport long-viewed as the flagship of the Olympic Games.

Just 270 days out from the start of the 2016 Rio Olympics, an independent commission set up by the World Anti-Doping Agency (WADA) will release its findings into a scandal already viewed as more damaging than the corruption crisis engulfing world football governing body FIFA.

"This is going to be a real game-changer for sport," said the report's co-author Richard McLaren.

"You potentially have a bunch of old men who put a whole lot of extra money in their pockets through extortion and bribes."

The commission, chaired by former WADA president and Canadian lawyer Dick Pound, will report on allegations of doping which were first aired in a German TV documentary in December 2014.

That programme claimed Russian track and field was plagued by doping.

The Sunday Times and the ARD channel also obtained a database belonging to the International Association of Athletics Federations (IAAF) which contained more than 12,000 blood tests taken from around 5,000 athletes between 2001 to 2012.

Allegations snowballed last week when the Mediapart news website claimed that Russian athletics chiefs and the sons of the former world body president Lamine Diack blackmailed athletes suspected of doping to let them keep competing.

Mediapart said it has seen the report which will be made public on Monday.

French police last Tuesday charged 82-year-old Diack with corruption over suspicions he took bribes worth over $1 million.

Mediapart also said six Russian athletes, including top marathon runner Lilya Shobukhova, were the targets of blackmail attempts by Russian athletics federation officials.

It quoted the WADA report as saying Shobukhova, who had her ban reduced after giving evidence to IAAF investigators, handed over $569,000 between 2012 and 2014 to a Russian coach, Alexey Melnikov, who acted as an intermediary.

The report added that Diack's two sons, Pape Massata Diack and Khalil Diack, were alleged to have asked for $500,000 from Turkey's 1500m women's Olympic champion Asli Cakir Alptekin in November 2012, but she refused.

Alptekin was suspended in April 2013 for abnormal blood samples and is now serving an eight-year ban and has been stripped of her London Olympics and European titles.

Papa Massata Diack will face charges for various alleged breaches of the IAAF Code of Ethics.

He will be joined by three others at a private hearing before a Panel of the Ethics Commission in London on December 16-18.

They are Valentin Balakhnichev, former president of the All-Russia Athletic Federation (ARAF), Melnikov, former chief coach of Russia's long distance walkers and runners, and Gabriel Dolle, former director of the IAAF's Anti-Doping Department.

Balakhnichev had stood down as IAAF treasurer at the same time as Papa Massata Diack's resignation, while Dolle was also charged with corruption by French police.

Current IAAF president Sebastian Coe on Sunday expressed his "shock, anger and sadness" at the allegations of high-level bribery.

"I'm shocked, angry and largely saddened," Coe told AFP.

"The allegations that we woke up to around the potential for extortion and blackmail came out of the blue and the vast majority in the sport probably share exactly the same emotions I've just expressed. It's shock, anger and sadness."

Coe, a two-time Olympic 1500 metres gold medallist for Britain, insisted that the IAAF's anti-doping strategy was not completely flawed.

"Our sport was the pioneering partner in the blood passport," he said. "It was introduced in 2009 and the very first sanction was in place in 2011.

"Since then, through the use of the blood passport there have been 85 sanctions in the whole of sport and 69 of them have come from athletics. That's more than any other sport and more than every other sport put together and interestingly more than through any national anti-doping agency. So no, we're not complacent."