The 28-year-old, a seven-time cross-country world champion, tested positive for anabolic steroid clostebol while training in Italy last September. 

She claimed to have used the substance inadvertently via a sun cream 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".

The Norwegian skier, who claimed 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 on Tuesday (March 7) that its Doping Panel deems the ban handed down by the Norwegian Olympic and Paralympic Committee and Confederation of Sports’ (NIF)  to be "on the low end of the range of reasonable sanctions" and that it had filed an appeal.

CAS has now acknowledged they have received the appeal and has opened proceedings but has not confirmed a date when a hearing will take place.

"The FIS requests that the period of ineligibility imposed on the athlete be 'reasonably extended'," read a CAS statement.

"A CAS arbitration procedure is in progress.

"First, the parties will exchange written submissions and a panel composed of either one or three arbitrators will be constituted.

"The panel will then issue directions with respect to the holding of a hearing.

"Following the hearing, the panel will deliberate and, at a later date, issue a decision in the form of an arbitral award."

The NIF 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 her 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 next season.

Johaug, a member of Norway's winning 4x5 kilometres relay team at the 2010 Winter Olympics in Vancouver, is a big star in her home country. 

She has previously claimed that she finds it "very strange" that people do not believe her reasoning for the failed test.

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

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