Olympic and world champion swimmer Sun Yang's short suspension for a doping violation in May was "appropriate", a senior Chinese anti-doping official said on Monday, defending the delayed announcement and lenient punishment.

The China Anti-Doping Agency announced on its website on Monday that Sun tested positive for the stimulant trimetazidine at an in-competition doping test during the national swimming championships on May 17.

Sun was then suspended from competition for three months and stripped of the 1,500m freestyle title he won at the national meet by the Chinese Swimming Association, which also fined him 5,000 yuan ($815).