Johaug, an Olympic gold medallist and seven-time world champion, tested positive for anabolic steroid clostebol while training in Italy in September of last year.

She claimed to have used the substance inadvertently via a sun cream that was wrongly given to her by a team doctor.

Anti-Doping Norway argue she should be blamed for "not having undertaken further investigation of the drug she received and used", which reportedly came in a package marked with the word "doping".

However, the skier, who said she used the sun cream to treat cracked lips, insisted her doctor had given her the all-clear to use the substance.

The FIS said in a statement released today that its Doping Panel deems the ban handed down by the Norwegian Olympic and Paralympic Committee and Confederation of Sports’ (NIF) Adjudication Committee to be "on the low end of the range of reasonable sanctions" and that it has filed an appeal to CAS.  

"[The sanction] fails to adequately reflect the fact that the athlete Therese Johaug failed to read the doping warning label printed in red on the package despite the fact that the medication was unknown to her and was purchased in a foreign country," the statement reads.

Austrian-based ski manufacturing giants Fischer Sports terminated their sponsorship agreement with Johaug last month as a result of her suspension. 

However, they said that they would not rule out working with Johaug again in the future once she has served her doping ban.

The move was widely expected due to a clause Fischer, one of the world's leading suppliers of skiing equipment, inserts into all sponsorship contracts.

It still represents a blow to Johaug as the deal was reported to be worth millions per year.

Jørn Ernst, Johaug's coach, told Norwegian newspaper VG the contract with Fischer was "very important" to the skier, who was a member of the 4x5 kilometres relay team which won the Olympic gold medal at Vancouver 2010.

The NIF’s Adjudication Committee confirmed last month that Johaug's suspension will be backdated to October 2016, meaning she will be able compete at the 2018 Winter Olympic Games in Pyeongchang.

Their verdict was received by Anti-Doping Norway's Prosecution Committee, who had originally called for the 28-year-old to be banned for 14 months.

A provisional suspension which was originally due to expire on December 18 was extended to February 19 of this year meaning Johaug - the reigning World Cup champion - has not competed this season.

She will be able to return to competition in November 2017, around the same time as the start of the season.

Johaug is a big star in Norway and has previously said that she finds it "very strange" that people do not believe her reasoning for the failed test.