The IAAF official spoke on condition of anonymity because the case has not yet been made public.
Greek media published a letter attributed to Kyriakos Chondrokoukis saying his son had tested positive for the steroid stanozolol. He said his son has not taken any banned substance and has asked for the backup "B'' sample to be tested.
"Despite the fact that we consider this news to be surreal, we do not wish to dispute the result of this test," the letter said, adding that Chondrokoukis and his father might also seek to have both samples later tested at a separate accredited laboratory.
"The paradox of the use of such an easily detectible banned substance by a recent world champion who is under the microscope of doping control authorities, and on the eve of the Olympic Games, is blatantly obvious," Kyriakos Chondrokoukis wrote in the letter. "Against this paradox I will fight, we will fight, to answer and determine what exactly happened."
The 24-year-old Chondrokoukis was expected to be a strong medal contender at the London Games after winning the world indoor title in Istanbul in March.
Chondrokoukis finished fifth at the 2011 world championships in Daegu, South Korea, and matched his personal best jump of 2.32 metres at the Doha Diamond League meet in May.
IOC spokesman Mark Adams said he had read media reports about the case, but said it was an IAAF matter.
"If we are catching people with pre-games testing, it can only be a good thing. We applaud it," Adams said. "The more drug cheats we can catch the better."