Olympic champion Sally Pearson will not defend her 100-metre hurdles crown at Rio 2016 after a hamstring tear forced her withdrawal.

Four years ago Pearson set a new Olympic record as she took gold in London ahead of Dawn Harper and Kellie Wells, the Australian clocking a time of 12.35 seconds.

Pearson was due to have been Australia's track and field captain at the Games after recovering from a year-long absence with a broken wrist and Achilles problems.

However, she will not be in Brazil after confirming she had torn a muscle during training ahead of August's competition.

"It is a hard time for me at the moment - I'm disappointed and I'm gutted," Pearson told the Nine Network.

"It's not so much just like a torn hamstring and you'll be right in a couple of weeks, it is a tendon injury.

"The biceps femoris has two heads and I split those two heads.

"Doing something like that in a tendon injury, it takes a long, long time to get better. Any tendon injury in the body takes a long time to heal.

"And unfortunately seven weeks out [from Rio], I have done a tendon injury and it's not going to allow me to get back in time for the Olympics."