Japanese swimming star Rikako Ikee has described battling leukemia as "several thousand times harder than I imagined" ©Getty Images

Japan's swimming star and home Tokyo 2020 medal hope Rikako Ikee has said battling leukemia is "several thousand times harder than I imagined" in a post on Twitter.

The 18-year-old, who won six gold medals at last year's Asian Games in Jakarta and was named the multi-sport event's Most Valuable Player, had been widely tipped to excel at next year's Olympic Games in Tokyo, but was diagnosed with the disease - a form of cancer - last month.

The multi-national record holder, who set Asian Games records with all six of her gold medal performances in Indonesia, was diagnosed after feeling unwell during a training camp in Australia and has now taken to Twitter to reveal how battling the condition is going.

"It is tens of times, several hundred times, several thousand times harder than I thought," she wrote.

"I haven't eaten rice in more than three days.

"But I don’t want to lose."

The swimmer's diagnosis has shocked Japan  ©Getty Images
The swimmer's diagnosis has shocked Japan  ©Getty Images

With Ikee hoped to be one of the poster girls of next year's Games, her diagnosis announcement last month sent shockwaves across Japan.

The country's Olympics Minister Yoshitaka Sakurada was forced to apologise just a day afterwards after he said Ikee's illness could dampen her team-mates' excitement for the Games.

"I'm really disappointed," he said.

"When one person leads, she can boost the whole team.

"I am slightly worried that this type of excitement could wane."

After being accused of not caring about the teenager's wellbeing, he later said her recovery is "the most important thing".

Because of her illness, Ikee - a three time world junior champion - will be forced to miss the upcoming World Aquatics Championships in South Korea in July.

She has also withdrawn from Japan's National Championships in April.