The duo were implicated in the Operation Aderlass investigation, which has led to the arrest of athletes from sports including skiing and cycling for their alleged involvement in the doping ring.

The operation was launched after Austrian skier Johannes Dürr made revelations about blood doping in an ARD documentary, which sparked raids conducted during the Nordic Ski World Championships in Seefeld and in Erfurt in Germany earlier this year.

Preidler and Denifl were among seven cyclists implicated in the scandal, the pair having been provisionally suspended by the International Cycling Union.

Austrian National Anti-Doping Organisation have now confirmed Preidler and Denifl will serve four-year bans.

Both were found to have used "autologous blood doping", the manipulation of blood and blood components.

Denifl had been deemed to have used the prohibited method from at least June 1 in 2014 through to the end of 2018.

Preidler was judged to have committed the same offence from at least February 1 in 2018 to December 23 of the same year.

Both riders will serve bans from the date of their provisional suspensions on March 3 through to March 4 in 2023.

The duo have also been stripped of results and prize money from between the dates they were deemed to have committed the offences.

This will see Denifl lose his overall victory at the 2017 Tour of Austria, as well as a Grand Tour stage victory at the Vuelta a España in the same year.

Both riders could yet lodge appeals against the sanctions.

The International Cycling Union (UCI) says it respects the decisions, but will make no further comment with investigations ongoing.

“Since it was agreed that the disciplinary proceedings would be conducted by the Austrian Anti-Doping Organisation, the UCI will recognise these decisions, upon expiration of the deadline to appeal,” a UCI statement read.

“The UCI and the CADF will continue to cooperate with and assist all parties involved in the Aderlass investigations but, in view of the nature of the ongoing investigations, will not make any further comment at this stage.”

At least 21 athletes from eight countries and five sports – three winter and two summer – are suspected of blood doping after police in Germany and Austria launched a targeted operation against what it believes is a worldwide drugs network.

Four cyclists – Italy’s Alessandro Petacchi, Croatia’s Kristijan Đurasek and Slovenians Kristijan Koren and Borut Božič – were provisionally suspended in May.

Austrian mountain bike athlete, Christina Kollmann-Forstner, was also provisionally suspended in the same month.