SYDNEY (REUTERS) - Sport Integrity Australia (SIA), which oversees doping control in the country, is to appeal the halving of the ban imposed on swimmer Shayna Jack at the Court of Arbitration for Sport (CAS), the body said on Monday (Dec 7).

Jack was banned for four years by the Australian Sports Anti-Doping Authority (Asada) after the freestyle swimmer tested positive for the banned anabolic agent Ligandrol in 2019.

The 22-year-old has always maintained that she would never wittingly ingest a banned substance and said she felt vindicated when her suspension was cut to two years by CAS, the highest legal authority in sport, last month.

SIA, the government agency which replaced Asada in July, said on Monday that after "careful consideration of the legal issues" it had decided to lodge a case with CAS Appeals Division.

"Sport Integrity Australia will always act to ensure a level playing field for athletes," chief executive David Sharpe said in a statement.

"In order to protect athletes and sporting competitions, we must have clarity and consistency in the application of the World Anti-Doping Code."

CAS backdated Jack's two-year ban to the date of her provisional suspension, a few days before the world swimming championships in South Korea in 2019, which would have allowed her to return to competition in July 2021.