(BSS/AFP) - Australian Olympic champion Mollie O`Callaghan said Wednesday she had been told to "stop swimming immediately" last month because of spinal stress fractures, but has been cleared to race at next week`s Commonwealth Games.

O`Callaghan, the reigning Olympic 200m freestyle champion, revealed her anguish in the run-up to the games in Glasgow, which begin on July 23, and the Pan Pacific Swimming Championships in California in August.

"Last month I was told I wouldn`t be able to compete at Trials, the Commonwealth Games or Pan Pacs. I was also told to stop swimming immediately," the 22-year-old posted on Instagram.

"It was a moment that reinforced just how much representing Australia means to me and how badly I want to be part of this team."

Scans showed stress fractures and bone oedema on her lumbar spine, O`Callaghan said, and her team sought advice from a spinal specialist.

After "further assessment" following the swimming trials, O`Callaghan said she was given the green light to compete at the Commonwealth Games and the Pan Pacific championships.

O`Callaghan is entered in three individual events in Glasgow -- the 100m and 200m freestyle, and 50m backstroke -- and several women`s and mixed relays, but she hinted her schedule could change.

"Things might look a little different for me at the Commonwealth Games and Pan Pacs but I`ll give everything I have and do my absolute best every time I race," she said.

O`Callaghan`s health revelations came a day after fellow Australian swimmer Shayna Jack announced she will retire from competition after the Commonwealth Games.

"I`m ready to announce my retirement and be Shayna Jack," she said in an emotional video recalling how "life blew up for me in 2019".

With the 2020 Games in her sights, her world came crashing down after testing positive for the muscle growth agent ligandrol in an out-of-competition test in June 2019.

She was banned for four years despite proclaiming her innocence, insisting the substance entered her system by contamination.

"I want to go out there, head held high, proud of who I am, proud of who I am representing and proud of what I am saying goodbye to," Jack said.