The detection of a new designer steroid in the United States could lead track and field's world governing body to bring back four–year bans for drug cheats.

The International Association of Athletics Federations said yesterday it may consider doubling its two–year penalty for athletes testing positive for steroids or other serious banned substances.

"Everybody in a responsible position is looking for a way to root out all of this," IAAF general secretary Istvan Gyulai said. "Obviously, one very logical approach would be to look at what happens if the sanction is more severe."

The IAAF reduced it penalty for steroid offenses from four years to two in 1997 after courts in several countries refused to uphold the longer ban. "I'm not sure it is easier now to enforce it," Gyulai said.

Current rules call for a "minimum" two–year suspension, but few countries opt for a stiffer penalty.

The push for tougher sanctions follows the unmasking of the designer steroid THG, or tetrahydrogestrinone, and a spate of positive tests for the stimulant modafinil.

Gyulai said the IAAF is also considering ways of punishing any coaches, trainers, doctors and agents implicated in the doping cases.

USA Track & Field has announced a "zero–tolerance" anti–doping plan which could include lifetime bans for first steroid offenses.

Four US athletes, including middle–distance runner Regina Jacobs and shot putter Kevin Toth, and British sprinter Dwain Chambers have tested positive for THG. Each is awaiting the analysis of their backup B samples.

THG was detected after an anonymous track coach tipped off the US Anti–Doping Agency and provided a used syringe containing the substance. The UCLA doping control laboratory identified it as a steroid – deliberately modified to evade detection – and devised a test for it.

The USADA ordered samples retested from the US track championships in June at Stanford. The IAAF is to retest 400 urine samples from the World Championships in Paris in August to check for THG.

Six US athletes have tested positive for modafinil, a prescription drug for the sleep disorder narcolepsy. They include sprinter Kelli White, who stands to lose her World Championship gold medals from the 100 and 200 meters.

Modafinil, classed as a minor stimulant, carries a public warning and disqualification from the event where the test took place, but no ban.