A television documentary due to be shown by German public broadcaster ARD on Wednesday evening said as many as 400 athletes missed tests in 2006 without being punished.

Media reports on Wednesday said that among the athletes, Olympic discus champion Lars Riedel had missed five doping tests.

Thomas Bach, who is president of the German Olympics Sports Association (DOSB), called on the national anti-doping agency NADA for a full report.

"We have asked for a report from NADA on these individual cases," Bach said. "Only then can we assess if and to what extent athletes have actually missed training controls."

Tightening controls

Under NADA rules, athletes missing a test for the first time without valid reason should receive an official warning.

"If these claims are confirmed there must be drastic action and NADA will be called upon to improve the control system," DOSB director Michael Vesper told Deutschlandfunk Radio.

A second missed test should bring a suspension of at least three months, a third missed test a one-year suspension and a fourth missed test a two-year ban.

Forty-year old Riedel, who is a five-time world champion and 1996 Olympic champion, denied missing five doping tests, but admitted he had missed one.

Too much work

Helmut Digel, vice-president of the international athletic federation IAAF told Deutschlandfunk that if Riedel was responsible for missing five tests he should be banned for two years.

According to Digel, the German anti-doping agency does not have enough staff and is "completely unable to cope." If the fault was with NADA and if Riedel was not properly informed, he could not be blamed for missing the tests.

The ARD documentary claims that some 400 of 4,500 athletes missed doping controls last year. They included seven Olympic champions, 32 world champions and 28 European champions.

ARD doping expert Hans-Joachim Seppelt said this did not mean the athletes were at fault.

"Sloppiness from controllers and other reasons are definitely possible," he said.