Pearson has been battling an Achilles tendon injuries leading into the Games but has been unable to overcome the injury.

She was set to compete in the women's 100m hurdles and 4x100m relay.

Pearson started 2018 as the reigning world champion, admitted the injury had been a long-term issue.

"It has been an ongoing issue for a couple years now," she said.

"I did everything I could possibly do, I left no stone unturned to race for Australia," Pearson said. 

She had won gold in the 100m hurdles at the 2010 and 2014 Games but was forced to pull out of the Rio Olympics with a hamstring injury.

Pearson had been racing in the lead up to the Games but during training, she couldn't do it and said her health came first.

She chose to pull out of the Games to take care of her health and injury in the lead up to Tokyo 2020 and was upset with the decision she had to make.

"I was absolutely gutted, there were a lot of tears flowing and a lot of emotions," she said.

"I was double checkings, triple checking that this was the right decision and that there was no other possible decision to make," Pearson said.