UPDATED 10.30am: Russia and Kenya have been subject to new doping allegations by a German broadcaster claiming evidence of runners using growth hormone, botched drug tests and widespread corruption.

ARD, who last December aired similar accusations of doping and corruption in Russia, returned to the controversy on Saturday just three weeks out from the world championships in Beijing.

"Despite assurances from the Russian authorities (in favour of a clean sport) doped competitors and their suppliers are always protected," the public broadcaster said in a statement.

The makers of the film claim to have evidence of human growth hormone being used to boost Russian runners.

They also say that a hidden camera recorded 800m athlete Anastasia Bazdireva as praising the benefits of drugs.

"With anabolics, I have stiff muscles. But I can run. It's hard but it's OK. You feel different with anabolics," she is recorded as claiming.

Dick Pound, the former head of world anti-doping agency WADA, said the latest allegations were worrying.

"If all of this is true, then the problem is certainly more significant that what has been admitted so far," he said.

ARD journalists also said that they had been given access by an anonymous source to a database of 12,000 drug test results taken from around 5000 athletes between 2001 to 2012.

Results were examined by Australian haematologist Michael Ashenden.

"According to him, these tests leave no doubt over the fact that endurance disciplines at Olympics and world championships were contaminated by doping," added the ARD statement.

Journalists also returned to Kenya where they claim another hidden camera showed injections of "dangerous" doping products being administered.

The program claimed that there is "massive corruption" within the Kenyan set-up and "a desire to cover-up doping ... to the summit of the Kenyan athletics federation".

Kenya was rocked this year when marathon star Rita Jeptoo was banned for two years after being caught doping with the banned blood-boosting hormone EPO.

"Since 2006, I have not been forced to do a single blood test in Kenya," the 34-year-old is quoted as saying by ARD, adding that only urine tests were carried out.

After ARD's first expose into doping at the end of 2014, Russian Athletics Federation president Valentin Balakhnichev was axed from his job as treasurer of the International Association of Athletics Federations (IAAF).

In February he quit as president of the Russian body.

In the furore that followed, the Russian federation said it was intending to sue ARD over their doping allegations.