Australian Olympic track star Peter Bol said he was innocent and "in total shock" Friday after being provisionally suspended for failing an out-of-competition drugs test.

The 800-metre runner, who narrowly missed bronze when he finished fourth at the 2020 Tokyo Olympics behind Kenyan winner Emmanuel Korir, returned the positive result on January 10.

Athletics Australia chief Peter Bromley said Bol's A sample showed an Adverse Analytical Finding for performance-enhancing Erythropoietin Receptor Agonists (EPO).

The test was carried out in October.

"It is critically important to convey with the strongest conviction that I am innocent and have not taken this substance as I am accused," the Sudan-born Bol, a silver medallist at last year's Commonwealth Games, said on social media

The 28-year-old said he was in "total shock" when told that a urine sample had returned a positive test.

"To be clear, I have NEVER purchased, researched, possessed, administered, or used synthetic EPO or any other prohibited substance."

Bromley said Bol can have a second, B sample analysed to reconfirm the initial result.

"There are procedural fairness and investigative considerations that constrain how much we can say," he said.

"And at this point it would be inappropriate for Athletics Australia or anyone else to speculate about the specific details or pre-empt any outcome.

"However, what we can say is that learning about this adverse analytical finding was both extremely concerning and completely out of the blue."

Under the provisional suspension, Bol is not allowed to train or compete at a national, state or club level.