The International Association of Athletics Federations (IAAF) has appealed six decisions recently made by the Russian Anti-Doping Agency (RUSADA).

The appeals relate to the cases of Valeriy Borchin, Olga Kaniskina, Sergey Bakulin, Sergey Kirdyapkin, Vladimir Kanaykin and Yuliya Zaripova, all of whom have been served with doping bans in recent months.

Suspensions of three years and two months were handed to reigning Olympic 50 kilometre walking champion Kirdyapkin, Kaniskina - a now-retired gold medallist at the Beijing Olympic Games in 2008 and silver medallist at London 2012 in the 20km walk - and 2011 world 50km champion Bakulin.

The cases of Kirdyapkin and Kaniskina were backdated to October 2012, while Bakulin's sanction ran from December 2012.

Borchin, winner of an Olympic gold medal in the 20km walk in 2008, was suspended for eight years for a second offence, and Kanaykin received a life ban for a repeat offence.

Zaripova won Olympic gold in the 3000m steeplechase at the London Games three years ago, and was handed a backdated two-and-a-half-year ban.

The cases will now be heard by the Court of Arbitration for Sport.

"All six cases arose from the IAAF Athlete Biological Passport programme launched in 2009 and had been referred to the Russian authorities for adjudication in accordance with IAAF rules," read an IAAF statement.

"While the IAAF agrees with RUSADA that there is, in each case, sufficient evidence of an anti-doping rule violation and that there are aggravating circumstances justifying an increased sanction of more than two years, the IAAF disagrees with the selective disqualification of results applied by RUSADA as a consequence of the previous rulings."

The IAAF is still reviewing the case of Tatyana Chernova, who won heptathlon gold at the 2011 world championships in Daegu and was banned for two years after anabolic steroids were found in her system.