Jannik Sinner's lawyer has called the World Anti-Doping Agency's (WADA) appeal against the tennis star 'unnecessary' after he was originally cleared of wrongdoing in his doping case.

The two-time Grand Slam winner was adjudged by the International Tennis Integrity Agency's (ITIA) to "bear no fault or negligence" for twice testing positive for clostebol - a banned substance - in March this year.

But WADA claim that the judgement was 'not correct under the applicable rules' and are calling for Sinner, 24, to be banned for between one and two years from tennis worldwide.

In a statement released on September 26, WADA confirmed that it would be taking the case to the Court of Arbitration for Sport (CAS) following the ITIA's decision not to punish Sinner.

The statement read: "It is WADA’s view that the finding of 'no fault or negligence' was not correct under the applicable rules. WADA is seeking a period of ineligibility of between one and two years.

"WADA is not seeking a disqualification of any results, save that which has already been imposed by the tribunal of first instance."

Jamie Singer, who acted on behalf of the Italian in the first investigation, insisted that the appeal by WADA was "unnecessary" because the world No 1 has not been accused of gaining an advantage in his performances.

"They believe that he is somehow responsible for the actions of his team and for this reason they ask for him to be punished," Singer told Gazzetta dello Sport. "Jannik said he was surprised and sorry for this appeal that he did not expect.

"We were surprised too, to be honest. After Jannik tested positive for clostebol in an infinitesimal amount, the International Tennis Integrity Agency understood the sensitivity of the case and turned to an expert independent tribunal instead of ruling directly.

"We hoped that the experience of the three specialists of the Sport Resolution Panel, and their well-substantiated and documented judgments, would convince the parties that the matter had been resolved correctly."

WADA must submit their appeal brief by October 10, after which the CAS will announce a judging panel and decide a hearing date, with Singer expecting a conclusion to the case in "a few months".

"We are all aware that WADA has the full right to take this action, appealing was within its possibilities and we know how complicated the work of monitoring doping and the integrity of the world of sport is. Having said that, we believe that the appeal was really unnecessary," he added.

When asked why WADA asked (asked repetition) for a suspension but not the deduction of points and earnings from other tournaments, Singer said: "This request is completely reasonable. In fact, no one accuses Jannik of having taken advantage of clostebol in his performances. For this reason, it would be unfair to penalise him in the rankings or in his earnings.

"However, WADA believes that he is somehow responsible for the actions of his team and for this reason they ask for him to be punished. The suspension is the punishment they ask for what they consider negligence."