The head of New Zealand's anti-doping agency says athletes are failing to speak out against drug cheats within their codes out of loyalty to their team mates.
Drug Free Sport New Zealand chief executive Graeme Steel said the agency was making progress on its goals, but it was not helped by a culture of secrecy within some sports.
He told MPs at Parliament this morning that anti-doping organisations had not yet won the "war on drugs" in sports.
"We haven't won it. I think at least we're holding the line and certainly it's not as bad as it was."
He said there had been clear differences in athletes' dependence on banned stimulants in the last three decades.
"Athletes still dope, but they can't dope in that gross manner that the East Germans and so on were [in the 1980s]. And they're being caught up with.
Lance [Armstrong] thought he was scot-free, Marion Jones thought they were scot-free, but two, three, four years later the evidence emerges and they get done."
But he said that some factors were preventing further progress.
Asked by a select committee what change would be the most helpful to removing drugs from sports, he said: "If people would own up to what they know.
"The people in sport would tell us what they're hearing. If what happened in Australia at Cronulla and Essendon, if one person early on said 'this smells and I'm going to tell the right people', a lot of that could have been nipped in the bud.
"People still feel that they have some kind of responsibility to their mates, to their team-mates not to say this stuff rather than to all the other athletes to say it."
Mr Steel was asked by MPs about recent scandals, including rugby and rugby league players' use of sleeping pills.
He said these substances were not banned, but their use "suggests a mind-set that's accepting of using things for inappropriate reasons".
Athletes went through fads of trying alternative stimulants, and the latest craze at the Sochi Winter Olympics was inhaling xenon gas.
Mr Steel also spoke about the Australian anti-doping agency's investigation into drug use in the country's rugby league and Australian Rules competitions.
He understood that the Australian Sports Anti-Doping Authority's inquiry had found that doping was not widespread and it was mostly focused on one sports scientist.
"There is no evidence that we have been able to find of the equivalent person operating here in New Zealand.
"What we did discover is that there probably hasn't been sufficient investigation or scrutiny of people that are operating in that area in New Zealand."
He said Drug Free Sport had discussed this oversight with High Performance Sport New Zealand. The organisation also planned to "beef up" its relationships with police and Customs.