The 28-year-old asked the public to believe him until his B sample is returned, which he is set to be tested next month, saying he was "in shock" at the positive result.

"It is critically important to convey with the strongest conviction that I am innocent and have not taken this substance as I am accused," said Bol in a statement on Twitter.

"I ask that everyone in Australia believe me and let the process play out."

Bol stated last week he was informed that an out-of-competition urine test from October 11 showed he had tested positive for synthetic EPO, by the Australian Sports Anti-Doping Authority.

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

"I voluntarily turned over my laptop, iPad and phone to Sport Integrity Australia to prove this.

"I have requested the analysis of my B sample which will take place in February.

"Given the subjective nature of interpreting this kind of test, I have asked that the lab perform a second confirmation.

"Above all, I remain hopeful that the process will exonerate me.

"My career, hopes and dreams are literally hanging in the balance over these next few weeks, and I ask everyone to respect my privacy as I remain provisionally suspended."

Bol has been regarded as a positive refugee story in Australia, being born in Sudan before his family fled when he was just four years old due to the civil war.

When he was eight, Bol arrived in Australia, setting in Toowoomba.

He won the silver medal at Birmingham 2022 behind Kenyan Wyclife Kinyamal and in front of England's Ben Pattison.

Athletics Australia chief executive Peter Bromley said the adverse analytical finding was concerning.

"There are procedural fairness and investigative consideration that constrain how much we can say, 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," said Bromley in a statement.

"However what we can say is that learning about this adverse analytical finding was both extremely concerning and completely out of the blue, and we will support Sport Integrity Australia who are leading the investigation into the matter."

Bol came fourth at the Tokyo 2020 Olympic Games in the men's 800m.

At the 2022 Paris Diamond League, Bol set a new national record with a a time of 1min 44.00sec.

If his B sample is positive too, he could face a four-year ban, which could be reduced if contamination can be proven or no negligence from the athlete.