"It certainly is a positive signal and indicates a desire and wish to show the world that they want to have a clean sport," IAAF general secretary Istvan Gyulai said in a telephone interview from the federation's Monaco headquarters.

The American governing body USA Track & Field, which has been under attack after a series of doping controversies, agreed at its annual meeting on Sunday to call for lifetime bans.

The decision was immediately denounced as unenforceable by World Anti-Doping Agency (WADA) chairman Dick Pound, who condemned it as "some kind of grandstand play".

"(USATF chief executive) Craig Masback is a very good lawyer and he knows perfectly well that's unenforceable," Pound told Reuters.

Gyulai agreed lifetime bans would be difficult to enforce in some countries. After a series of court cases, the IAAF congress halved its four-year bans for serious drugs offences in 1997.

But Gyulai said the USATF proposal showed there was a world-wide concern with doping in all sports, not just in track and field.

"We must be certain that it can be implemented, especially in countries famous for litigation," Gyulai added. "There were serious difficulties in the 1990s. But the IAAF is very much for world-wide harmonisation."

Gyulai also added his support to Pound's call for USATF to hand over its documents relating to the Jerome Young doping case.

The world 400 metres champion tested positive for the steroid nandrolone in 1999 but was cleared by the U.S. federation to compete at the 2000 Sydney Olympics where he won a gold medal as a member of the 4x400 relay squad.

His identity was not released until he was named by a U.S. newspaper after winning the 400 gold medal at the Paris world championships in August.

Although the case is being reviewed by the International Olympic Committee (IOC), the U.S. federation has maintained it cannot release any information following a Court of Arbitration ruling.

"We would like this to be clarified," Gyulai said. "It's not good in the eyes of the public that this case is dragging on.

"It's very simple. The documents should be made available."