Tracking accomplices of doping cheaters, identifying new designer drugs, and finding a test for human growth hormone are the biggest problems facing anti-doping authorities.

Those predicaments were highlighted Saturday at the start of a three-day symposium organized by the International Association of Athletics Federations.

Anti-doping experts are bracing themselves for gene doping and new and unknown forms of drugs, IOC medical commission president Arne Ljungqvist said.

Athlete representatives lobbied for stricter ``whereabouts'' rules requiring competitors to provide anti-doping agencies with information on their location at all times so effective out-of-competition testing could be conducted.

``We have accomplished a lot but there are still many, many problems,'' said Ljungqvist, also an IAAF senior vice-president.

WADA sanctions those who administer banned substances or prohibited methods _ such as blood transfusions _ or even assisting, encouraging or aiding an athlete to cheat, but the difficulty is catching them.

``We need to find and follow the entourage of cheating athletes,'' Ljungqvist said. ``It's difficult to find them and for that you need government support.''

WADA is scheduled to meet with Interpol on Monday in an effort to enlist the world's largest international police organization in the fight against the trafficking of doping substances.

``There is more money to be made in the trafficking of steroids than trafficking of so-called social drugs,'' WADA director general David Howman said. ``Partly because it is legal in some countries.

``Individual governments have to say 'this is an evil in our societies,''' Howman added. ``Countries have people making money on what we think is the misery of teenagers in particular.''

New designer drugs were also difficult.

``Not just new versions of drugs acting in the same way, but completely new drugs acting in new ways,'' Ljungqvist said. ``We need more intelligence. We need to know more about what is happening out there and have people reporting back to us.

``HGH is on the list but at the time being there is no proper way to detect it. As for gene doping, we can see them around the corner, if they haven't already come around to this side of the corner.''

Gene doping involves transferring genes into human cells to blend directly into an athlete's own DNA. It is thought an athlete's stem cells could be injected back into the body. The regenerative powers of stem cells offer countless sporting possibilities, such as increasing endurance, speed, flexibility and strength.

Paula Radcliffe, the marathon world record-holder and part of the IAAF athletes commission, said athletes want anti-doping agents to be more persistent in finding athletes for out-of-competition tests.

Current rules require athletes to notify anti-doping agencies of their whereabouts at all times. But loopholes allow some athletes to get away with missing tests. Some train in countries where testers can't get to them because of visa problems. Athletes can also get off because testers gave up trying to find them too easily.

``They should use the technology available to locate us, like cell phones,'' said Mike Conley, a long and triple jumper. ``Every effort should be made to find athletes. There are a lot of reasons we didn't hear the doorbell: We were in the back yard, the music was too loud, we went to the store. There are a lot of reasons athletes are not exactly where they said they would be three months before.

``The trouble is these are excuses athletes can use as loopholes unless testers really do everything in their power to find them.''

Radcliffe suggested international anti-doping testers should have `diplomatic passports' to carry out unannounced tests in countries where visas requirements often hinder access.

Radcliffe continued to campaign for medical passports profiling individual athletes' physiological makeup to help anti-doping agencies identify abnormalities or detect sudden changes in an athlete's blood. WADA has been nursing the idea since 2001.

Another recent problem is the increasing number of cases in which B samples fail to confirm positive A samples. Howman said it was likely due to increased testing.

However, he said the accredited laboratories where tests were performed could not be blamed for leaks of results following a positive A sample.

``The laboratory has no idea whose test they are analyzing. They only have numbers, no names. The people most likely to leak are in the athlete's entourage,'' he said. ``We've carried out our own surveys into this which suggest that in 90 per cent of the cases the result leaked to the media is given by someone associated with the athlete, someone in the entourage.''