International Olympic Committee president Jaques Rogge says there is no doubt there is illegal drug use in rugby and it would be naive to think otherwise.
Rugby has had lower evidence of doping than many other international sports, but the International Rugby Board has not released drug testing results for this World Cup tournament.
Mr Rogge is in New Zealand for the Cup final on Sunday and talks with the New Zealand Olympic Committee.
Despite rugby's relatively clean record, he says there is no room for complacency.
Mr Rogge says prevention is the key to stamping out drug use in sport.