Rio 2016: Hurdles champion Sally Pearson pulls out of Rio Olympics

The 29-year-old, who won gold in the 100 metres hurdles at the London Olympics, had battled back after being sidelined for a year by a wrist injury only to suffer the hamstring injury training at her base on the Gold Coast, the Sun Herald said.

Person confirmed her withdrawal on Wednesday.

"Going over the hurdles, I felt two sort of squeezes in my hamstring, and my heart sank, it was very disappointing, but I thought it was just a hamstring tear, probably take me a couple of weeks and I’ll be alright,” the 29-year-old told 9NEWS.

"But, we went and got scans, and it showed it was actually a tendon tear. Any tendon in the body takes a long time to recover, I’ve had a few Achilles injuries, and they take the exact same amount of time.

“The risk of going to compete at the Olympics could do major damage to my hamstring, and there’d be no opportunity to come back and try to go to the Commonwealth Games on the Gold Coast in two years’ time.

"It’s heartbreaking and devastating that I can’t be in Rio, as the Olympic champion, and run at 100 percent and be proud to represent my country, it’s just not going to happen this year – my body won’t allow it."

Pearson's hopes of defending her title in Rio had looked slim after the fall at the Golden Gala meeting in Rome last year, which so badly shattered her wrist she feared her left forearm might need to be amputated.

The 2011 world champion, who also won silver in the event at the 2008 Games in Beijing, missed the back end of the 2015 season and only returned to racing in Europe early this month.

Her results in three races in Birmingham, France and Oslo were disappointing, however, and she returned for a period of intense training in the warmer climes of her home town on the Queensland coast.

"I have left nothing in the tank on my return," Pearson wrote in a post on her website 10 days ago.

"Training has been intensely hard and I am exhausted from it but at this stage I have absolutely no other choice if I am going to be competitive in Rio."

Pearson is likely to continue competing at least until the 2018 Commonwealth Games, which will take place on the Gold Coast.