Greece's top two sprinters at the heart of a doping investigation, which led them to withdraw from last month's Olympics, will appear before prosecutors for additional questioning next Monday.

Kostas Kenteris and Katerina Thanou are due to appear before state prosecutors for the second time regarding a missed doping test on the eve of the Athens Olympics in August and a motorcycle accident hours later, court officials said.

Kenteris, Olympic 200 metres gold medallist in Sydney, and Thanou, who won a 100 meters silver medal in the 2000 Games, are suspected of obstructing a doping test and giving a false report to authorities.

"This time their appearance will not be that of witnesses to the investigation but as suspects of two specific actions," a court source told Reuters on Thursday.

The two athletes failed to appear for a scheduled doping test inside the athletes' village a day before the start of the Olympics and reported to police they crashed their motorcycle hours later.

SUSPECT TESTIMONY

Prosecutors have also called back the only witness to the crash, the man who drove the two sprinters to hospital where they remained for four days amid a whirlwind of publicity and anger and confusion among Greeks.

They had been regarded as the host country's best hopes for athletics gold. Kenteris, in particular, was a national hero and had been earmarked for the honour of lighting the Olympic flame, according to local media.

"There are several differences in the versions of the athletes and the witness as to what happened that night," a prosecutor's source said adding there were also discrepancies regarding the injuries sustained in the crash.

Doctors said at the time the pair suffered head, body and leg injuries but a medical examiner who was called in following the crash only found that Kenteris had minor cuts and bruises while Thanou did not have any visible injuries at all.

The sprinters' lawyer said the suspicions had no legal basis.

"The obstruction of a doping test is a disciplinary matter and not a criminal offence and cannot stand up because they did not avoid being tested," Michalis Dimitrakopoulos told reporters on Thursday.

The athletes say they were not informed of any doping test and they heard about it in the news several hours after the deadline for their appearance.

Their long-time coach Christos Tzekos, who has since been fired by Kenteris, has also testified over the incident and the discovery of a stash of banned stimulants and steroids found in a warehouse of his nutritional supplements company.