Five-time grand slam champion Iga Świątek has accepted a one-month suspension after testing positive for a banned substance, but she will be able to play the Australian Open in January.

The International Tennis Integrity Agency (ITIA) announced Świątek tested positive for trimetazidine, a heart medication known as TMZ, in an out-of-competition drug test in August.

The ITIA accepted her explanation that the result was unintentional and caused by the contamination of a non-prescription medication, melatonin, that Świątek was taking for issues with jet lag and sleeping.

It was determined her level of fault was "at the lowest end of the range for no significant fault or negligence", according to the ITIA.

World number two Świątek said in a video she posted on social media that this was "the worst experience of my life".

"The whole thing will definitely stay with me for the rest of my life," the 23-year-old said, speaking Polish with English subtitles.

"The worst part of it was the uncertainty. I didn't know what was going to happen with my career, how things would end or if I would be allowed to play tennis at all."

The Women's Tennis Association (WTA) said it "fully supports" Świątek.

"Iga has consistently demonstrated a strong commitment to fair play and upholding the principles of clean sport, and this unfortunate incident highlights the challenges athletes face in navigating the use of medications and supplements," the women's tour said in a statement.

"The WTA remains steadfast in our support for a clean sport and the rigorous processes that protect the integrity of competition. We also emphasise that athletes must take every precaution to verify the safety and compliance of all products they use, as even unintentional exposure to prohibited substances can have significant consequences."

Świątek formally admitted the anti-doping rule violation this week and accepted her penalty.

TMZ is the drug at the centre of the case involving 23 Chinese swimmers who remained eligible despite testing positive for performance enhancers in 2021.

Świątek said she was "shocked" by her test result and had never heard of TMZ.

She said she has been using melatonin "for a long time", adding that she could not sleep without it due to "all my travelling, jet lag and work-related stress".

She was already provisionally suspended from September 12 to October 4, missing three tournaments during the post-US Open hard-court swing in Asia, but that provisional ban was ended after her appeal showed her test result came inadvertently from contaminated melatonin.

Because the ultimate agreement was for a month suspension, she will serve the remaining eight days now, while there is no competition, and be cleared to return to play as of December 4, in plenty of time for the start of the 2025 season in Australian later in the month.

"I can start my new season with a clean slate, focused on what I've always done — simply playing tennis," said Świątek, who hired Wim Fissette as her coach in October.

Świątek also was fined the prize money of $158,944 that she earned for her semifinal run at the Cincinnati Open in August, the event immediately following the positive test.

This is the second recent high-profile doping case in tennis after men's world number one Jannik Sinner failed two tests for a steroid in March and was cleared in August, right before the start of the US Open.

Sinner won the New York slam and did not miss any competition, although the World Anti-Doping Agency has appealed the ruling that exonerated him.

AP