Australian champion Sally Pearson's bid for a third straight Commonwealth Games 100m hurdles title is over, just as the Gold Coast Games begin.

Pearson has been battling an Achilles problem since late February, although she did run a leg of a 4x100m relay last week in Brisbane.

The co-captain of the Australian athletics squad confirmed the news on Thursday, saying she was "gutted" when the ongoing injury flared up two days ago at training.

"I went into some hurdle drills and run throughs and just couldn't do it," the Gold Coaster told a packed media conference.

"The thing with tendons is they spike very quickly ... it's tough the timing comes now, but my health comes first."

The 31-year-old said the injuring was affecting her ability to hurdle, but she could do flat sprints.

Last Saturday, she rated herself a "90 per cent chance" of being on the start line for the opening round of the 100m hurdles on April 12.

Sitting next to Australia's athletics head coach, Craig Hilliard, and team doctor Paul Blackman, on Thursday, Pearson admitted there was now too much pain to compete.

She said it was hard to cope with the disappointment but she had to manage the injury to keep her glittering career going.

"Gutted, tears flowing, a lot of emotions, you could call it grief," she said of her emotions.

"(I've been) going through the numb phase first then the crying phase and then speaking to Craig and Paul and double and triple checking it was the right decision."

Pearson, who was aiming for a third straight Commonwealth gold medal, confirmed she still intends to defend her world championships gold medal, with the aim of contesting the Tokyo 2020 Olympics.

For now, the focus is overcoming the "rollercoaster" of the Achilles injury that has impeded her decorated career and contributed to her withdrawal from the Rio Olympics.

"This year I'll be rehabbing it for the world championships next year, and then Tokyo it's important I can be at my best. I won't be running for the rest of the season," she said.

Blackman said tendon injuries were notoriously difficult to predict.

"We've got a unique opportunity in the current cycle to clear this," Blackman said. "It's really difficult to look ahead past the next month or two at this point."

After winning her second Commonwealth title in Glasgow in 2014, Pearson suffered a series of serious wrist, hamstring and Achilles injuries which ruled her out of the 2015 world titles and the Rio Olympics.

But she made a triumphant return to the global stage last year, coaching herself to a second world title in London.

As a proud Gold Coast local, Pearson has been one of the faces of the 2018 Games. She was given the honour of delivering the Queen's message to Prince Charles at the opening ceremony on Wednesday night.