Paris – All Blacks great Dan Carter insists he has never come across banned substances in rugby, after himself being cleared in a doping probe. Carter, fellow former All Black Joe Rokococo and Argentinian winger Juan Imhoff, who all play for Racing 92, were the target of an investigation by the medical commission of the French Rugby Federation after testing positive for corticosteroids following last season’s Top 14 final. But the trio, as well as Racing’s medical staff, were all cleared of any wrongdoing. Speaking to franceinfo in an interview, Carter said he had never encountered doping in rugby. “No, never, right throughout my career,” said the flyhalf, capped 112 times by New Zealand and a two-time World Cup winner. “I have huge confidence in the authorities that keep this game clean. “I hold my integrity and the game’s integrity at the highest level and I have full trust that the authorities are making sure that this game is kept clean under the anti-doping regulations – and they’ve put a lot of procedures in place to make sure that it is. “I have full confidence our game is played in a clean way and am confident it will continue to be that way for a long time.” Carter explained that he had a corticosteroid injection after Racing’s Top 14 semi-final victory over Clermont, when he picked up a swollen knee. “The following two days complete rest and then I was able to play following that,” he said, with him and Rokocoko going on to notch up 20 points between them in Racing’s final win over Toulon. “I have full trust in the medical team and am extremely confident that we stayed within the anti-doping regulations which has been proven we did.” When asked whether he thought others abused the use of corticosteroids, Carter said: “I can’t really speak for other people, other athletes, other rugby players. “For me I had an injury. When you have an injury you want to cure the injury within the anti-doping regulations and that’s exactly what I did.” Carter, who made his debut for the All Blacks in 2003 admitted, however, the temptation might be there given the seismic changes the ever-increasing rate of professionalism brings although he argued that was countered by the staggering advances in the better nurturing of players. “The game has definitely changed, it’s a lot more demanding,” said the world record Test points scorer . “The players are stronger, the game is faster.