A Russian bobsledder who previously boasted of being a 'clean' athlete faces a ban from the Winter Olympics for doping.

Nadezdha Sergeeva recently competed in the two-man Women's Bobsleigh event and finished 12th in the competition final on February 20. Organisers say she tested positive for an a banned stimulant, which Associated Press reports was trimetazidine. Sergeeva denies taking the drug.

Trimetazidine is a prescription medicine which increases oxygen to the heart and lungs but is illegal under Wada anti-doping rules.

The chairman of the Russian bobsled federation, Alexander Zubkov, says his organisation is now preparing a defence for Sergeeva, stating she had passed a doping test five days earlier.

Sergeeva is a 30-year-old bobsledder from Kemerovo, Russia and recently appeared in a promotional video where she wore a t-shirt that read: "I Don't Do Doping."

The incident marks the second time a Russian athlete has tested positive during this year's competition and may dash hopes that the country be officially reinstated for the Olympic Games closing ceremony.

Russian curler Aleksandr Krushelnitckii, who had won bronze in the mixed doubles, also tested positive this week for banned substance meldonium. Both he and his partner were forced to hand back their medals.

The Russian Olympic Federation is currently serving a ban for its state-sponsored doping program operated during the 2014 Sochi Winter Olympics Games.

However, IOC authorities allowed 169 previously clean athletes to participate in the competition under the OAR banner, or Olympic Athletes from Russia. Under the agreement Russian athletes are not be able to compete under the national flag.

Nadezhda Sergeeva
Russian bobsledder Nadezhda Sergeeva is accused of taking a banned drug. Youtube