Olympic 800m runner Peter Bol said he had been exonerated after the Australian had his provisional doping suspension lifted on Tuesday, although investigations continue.

Sudan-born Bol was suspended in January when his "A" sample tested positive for performance-enhancing Erythropoietin Receptor Agonists (EPO).

Analysis of his "B" sample however resulted in an "atypical" finding for the banned EPO, Sport Integrity Australia said in a statement.

The 28-year-old's suspension has therefore been lifted, the anti-doping authority said, warning however that its investigation was not over.

An atypical finding is not the same as a negative test result, it said.

The out-of-competition samples were taken last October.

"The investigation into the matter remains ongoing. Sport Integrity Australia will, as part of its investigation, proceed to consider whether any anti-doping rule violation/s have been committed," the organisation said.

"It is not possible to provide a timeframe at this point."

Bol, who finished fourth at the Tokyo Olympics in 2021 and won silver at last year's Commonwealth Games, had denied wrongdoing throughout.

Athletics Australia said that Bol can now return to training and competition.

"The last month has been nothing less than a nightmare," Bol wrote on social media, adding that he wished that his "A" sample results had not been "leaked".

"To say it one more time: I am innocent and have not taken this substance as I was accused," Bol said.

"I have NEVER in my life purchased, researched, possessed, administered, or used synthetic EPO or any other Prohibited Substance, and never will."

Peter Bromley, chief executive of Athletics Australia, noted that the investigation against Bol was ongoing.

"It's a frustrating and confusing situation with a highly technical process, however it's important that the process is allowed to take its course," he said in a statement