The coach of two Greek sprinters facing two-year bans for missed doping tests accused Olympic officials on Sunday of incorrect notification procedures that forced his athletes to withdraw from the Games.

Coach Christos Tzekos and sprinters Costas Kenteris and Katerina Thanou are accused of avoiding a series of drugs tests including one on the eve of the Athens Olympics last August.

Tzekos told an athletics disciplinary committee the pair had never avoided being tested, contradicting a top doping official who said they could not be found in the athletes' village to undergo testing.

"There are two ways you can see a subject but it is up to the committee to decide," he told reporters after testifying. "We presented the reality as we lived it."

Asked whether doping officials had followed all procedures, Tzekos said: "Not all, not all. The (disciplinary) committee will answer about this."

Kenteris, 31, the defending men's 200 metres champion, and Thanou, 29, who won the women's 100 metres silver medal at the 2000 Sydney Games face a two-year career-ending bans if found guilty.

They were scheduled to testify later in the day.

The head of the athletes' village doping centre said on Saturday that testers were looking for the Greek sprinters for two hours but could not find them.

"Everything was done according to the letter of the law. All procedures were followed correctly and according to the rules and regulations of the International Olympic Committee and WADA (World Anti-Doping Agency)," Dimitris Valassiadis said. "I looked for them for two hours but I could not find them."

Tzekos said they had never refused to turn up for testing.

"We were asked (by the disciplinary committee) all kinds of questions about the night of August 12."

"We did not leave any gaps...as far as I am concerned there is no such issue (of refusing to be tested), and I am very optimistic" said Tzekos, who also faces a criminal investigation linked to the import of illegal substances for his nutritional supplements company.

The athletes have been suspended by the International Association of Athletics Associations (IAAF) for missing three tests, including the one scheduled for Athens.

The disciplinary committee has been set up by the Greek Athletics Federation (SEGAS) following the IAAF suspension.

The IAAF has said the sprinters failed to provide samples for tests in Tel Aviv, Chicago and Athens within the space of a few months and ordered a SEGAS disciplinary committee.

They face a criminal hearing in Greece over the missed tests and have also been charged with faking a motorcycle accident on the day of the Athens test which led to them spending four days in hospital.