Women's tennis world number one Iga Swiatek has withdrawn from the Madrid Open due to begin on Thursday saying her "body needs rest" after a hectic schedule.

The 20-year-old Pole -- who became number one earlier this month on the retirement of Ashleigh Barty -- has won the last four tournaments she has played, the latest a straight sets demolition of Aryna Sabalenka last Sunday.

It is not the first time this season she has withdrawn from a tournament due to fatigue -- she pulled out of the Charleston event in early April.

"After intense last weeks and winning 4 titles in a row it's time to take care of my arm that has been fatigued since the Miami Open and I haven't had a chance to handle it properly," she wrote in a statement posted on her Twitter account.

"I need a break from playing so intensively in order to treat my arm well and that's why, unfortunately, I have to withdraw from the Madrid Open.

"My body needs rest."

Swiatek added she looked forward to competing in the upcoming Rome tournament -- which starts on May 9 -- and the French Open which she won in 2020.