World No.1 tennis player Jannik Sinner has tested positive twice for a banned anabolic steroid in March, but not been banned.

His escape has been lambasted by Australia’s Nick Kyrgios.

Sinner was stripped of $US325,000 ($482,300) prize money and 400 ranking points earned at the Masters tournament in Indian Wells, California, but will not be suspended after an independent tribunal said it was not intentional.

“Ridiculous – whether it was accidental or planned. You get tested twice with a banned substance … you should be gone for 2 years. Your performance was enhanced,” Kyrgios said on X.

Kyrgios followed up by telling a poster who defended Sinner: “Accidental? You truly believe that the physio rubbed physio cream onto a cut that made him fail 2 anabolic steroid tests. Cmon potato”

Sinner tested positive for low levels of a metabolite of clostebol during the event, in which he reached the semi-final, and eight days later.

Clostebol is a steroid that that can be used to build muscle mass, but is also found in products to treat swelling and irritation. It is listed as a prohibited substance by the World Anti-Doping Agency (WADA).

Sinner said the steroid entered his bloodstream after it was in a spray used by his physiotherapist, Giacomo Naldi, to treat a cut on the latter’s hand. It had been bought over the counter in Italy a month earlier by Sinner’s fitness coach, Umberto Ferrara.

“The physiotherapist treated Jannik without gloves and coupled with various skin lesions on Jannik’s body caused the inadvertent contamination,” a statement from Sinner’s lawyers said.

Sinner stated that he suffers from a skin condition on his feet and back that leads to scratching and can cause small cuts and lesions.

The International Tennis Integrity Agency (ITIA) announced on Tuesday they accepted this explanation and determined the violation was not intentional.

An independent panel held a hearing on August 15 and “determined a finding of No Fault or Negligence applied in the case, resulting in no period of ineligibility,” according to the ITIA.

“After each positive test, a provisional suspension was applied. On both occasions, Sinner successfully appealed the provisional suspension and so has been able to continue playing,” the ITIA statement said.

The ITIA described the levels found in Sinner’s sample as “low”. His lawyers said it amounted to “less than a billionth of a gram”.

ITIA CEO Karen Moorhouse said “Sinner and his representatives fully cooperated” with her group’s “thorough investigation.”

The decision is subject to appeal by WADA and the Italian Anti-Doping Agency (NADO Italia), the statement added.

“I will now put this challenging and deeply unfortunate period behind me,” Sinner said in a statement.

“I will continue to do everything I can to ensure I continue to comply with the ITIA’s anti-doping programme.

“I have a team around me that are meticulous in their own compliance.”

Sinner, who turned 23 on Friday, won the Australian Open in January for his first, and so far only grand slam title.

The Italian won the Cincinnati Open on Monday and will be among the favourites at the US Open, which starts in New York next week.