(BSS/AFP) - Five-time Olympic gold medallist Kaylee McKeown has pulled out of the lucrative World Cup swimming series in China to focus on her mental health.

The Australian star, who retained her 100m and 200m backstroke Olympic titles in Paris this year, made the decision after competing on day one of the leg in Shanghai on Friday.

"I would like to thank World Aquatics for the opportunity to come out and race at World Cups, it`s been so much fun here in Shanghai," she said on Instagram.

"Putting my mental health first, I`ve decided to cut my experience short. As an athlete it`s so important to listen to your heart and to know when enough is enough.

"Time for a well overdue break."

McKeown was a dominant force in the World Cup series last year, winning the overall women`s title and breaking multiple world records.

After her exploits at the Olympics, she was back in the pool just weeks later at the Australian short-course championships last month while many of her contemporaries rested.

She smashed the 100m short-course backstroke world record, saying at the time she was going "stir-crazy" sitting at home.

The World Cup series moves to South Korea next weekend before heading to Singapore.