Defending champion Simona Halep has withdrawn from next week's Dubai Tennis Championships with a lower back complaint, organisers of the WTA 1000 tournament said on Thursday.

World number three Halep, who also pulled out of this week's Qatar Open in Doha, has not played a competitive match since losing in straight sets to Serena Williams in the Australian Open quarter-finals last month.

"Unfortunately I am not feeling 100% in my lower back, and I have made the tough decision to withdraw from the 2021 Dubai Duty Free Tennis Championships," the 29-year-old Romanian, who also won the Dubai event in 2015, said in a statement.

"I have great memories from winning my 20th WTA title after some really tough matches in Dubai last year so I'm disappointed that I won't be able to defend my title."

Halep follows world number one Ash Barty, who is recovering from a leg injury, in skipping the Dubai event, which runs from March 7-13.