Greece asked the International Olympic Committee for a 48-hour stay of execution on Friday to allow its two top sprinters to explain why they missed a drugs test, risking expulsion from the Athens Olympiad.

Greek Olympic team manager Yiannis Papadoyiannakis asked for extra time after Costas Kenteris and Katerina Thanou, injured in a mystery overnight motorcycle accident, failed to appear at an IOC drug tribunal on Friday.

Kenteris was summoned to appear at 12.30 local time before the IOC panel at an Athens hotel. Thanou was scheduled to explain herself to the three-man jury half an hour later.

But the time passed with no sign of them leaving a special athletes' ward in a hospital where they were taken following a motorbike crash sometime after missing the dope test.

Sergei Bubka, a member of the tribunal, said: "They did not show up."

In a severe shock to a nation savouring one of its proudest moments, Kenteris, who won gold in the 200 metres in the Sydney Games and Thanou, who took silver in the 100, risked an image blow to Greece on the eve of the opening ceremony.

They had cast "suspicion, confusion and disappointment" over the Games, said an IOC member.

Unless they convince the IOC their actions were innocent, they may be banned from the Games, turning what was becoming an orgy of national hubris into a veritable Greek tragedy.

LEFT EARLY

International Association of Athletics Federations (IAAF) general secretary Istvan Gyulai told Reuters that Kenteris and Thanou missed a drugs test in Chicago several days ago after leaving for Athens a day earlier than planned.

"They came back a day early, this is our information," he said in Athens.

IOC president Jacques Rogge also confirmed neither athlete had undergone a drugs test at any stage on Thursday. The fact that they were Greek national heroes would have no bearing on their fate, he added at a news conference.

"We don't know what to believe. A shadow has been cast over the whole thing," said the IOC member who requested anonymity. Asked if the IOC felt the accident was suspect, he said: "Yes."

Kenteris and Thanou were visited in hospital on Friday morning and declared healthy. At the same time, they were ordered to appear before the three-member IOC drugs panel.

A missed drugs appointment is normally treated as a failed test, which carries a two-year ban.

A statement on their injuries in the crash, in which no other vehicle was involved, said Kenteris "sustained a slight head injury, a sprain to the vertebra at the back of his neck, a knee sprain and scratches to his right leg". Thanou suffered "slight abdominal injuries, a sprain to the right leg".

In the aftermath, Greek Olympic team spokesman George Gakis said the two sprinters were not out of the team and sprint coach Christos Tzekos said the two could be fit in time to compete.

"They don't have a serious problem. We'll see over the next few days how their health develops," said Tzekos. The women's 100 metres final is on August 21, the men's 200 on August 26.

But all Athens was staggered by the news. Call-in show reaction swung from sympathy to stoicism to paranoia. The daily Ethnos urged the sprinters "Tell Us the Truth - You owe it to all Greeks to prove you are clean".

One man, lamenting all the wrecked pride in Athens's glorious last-minute rescue of a Games that had often been declared on the verge of forfeit, said there was "a curse upon us".