The International Weightlifting Federation and its long-time chief Tamas Ajan have been accused of establishing a “culture of corruption” and doping cover-ups over decades in a German documentary to be aired Sunday.

Prominent weightlifters were rarely subject to tests, while some doping controllers were allegedly taking cash to accept manipulated urine samples, claimed the report by journalists at German broadcaster ARD including Hajo Seppelt, who broke the story on Russia's state doping scandal.

Dorin Balmus, doctor of the Moldovan national weightlifting team, was caught on hidden camera explaining how urine samples could be manipulated -- including by getting lookalikes of athletes to provide the samples.

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The undercover team also filmed Thailand's Olympic bronze medallist Rattikan Gulnoi admitting to using steroids when she was 18 years old -- something that could see her stripped of her prize.

Christian Baumgartner, who heads the German federation, told ARD the IWF's chief was to blame.

“Ajan stands for a system that has established doping in weightlifting over decades and that has gone off the rails for decades,” Baumgartner charged, adding that “a culture of corruption has spread”.

Beyond doping, the ARD report also cited documents allegedly showing at least $5 million in funding flowing from the International Olympic Committee to the IWF were transferred into two Swiss accounts of which only Ajan had oversight.

Hungarian national Ajan, 80, has been in the IWF's management since 1970, taking over as president of the federation in 2000.

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In a statement later Sunday, the IWF said it was examining the allegations made in the broadcast.

“Amid a number of apparent falsehoods, unsubstantiated allegations and disproven rumours dating back to as far as 2008, there does seem to be some fresh information included in the programme which may be of use to the IWF's efforts to promote clean weightlifting and protect clean sport,” said the statement.

“The IWF will move very quickly to investigate the issues raised in the show as quickly as possible, and has requested the transcripts and research materials.

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“The IWF takes these allegations very seriously and, where appropriate, will consider independent third-party assistance in investigating these matters.”

Seppelt and the ARD team was behind a documentary film in 2014 that sparked an official investigation into state doping in Russia that saw it banned from key international sports events.

Anti-doping organisation WADA decided on December 9 to ban Russia from participating in major international events for four years, including the 2020 and 2022 Olympic Games and the 2022 World Cup.