Former WBO world heavyweight champion Joseph Parker failed a drugs test for cocaine on the day of his 11th-round stoppage defeat by Fabio Wardley, it has been revealed.

The 33-year-old was tested by the Voluntary Anti-Doping Agency (VADA) and the adverse analytical finding was revealed on Friday morning, per a report in The Sun.

Two sources close to Team Parker have conveyed their dismay to The Ring at the findings, for which he has an opportunity to have his B-sample tested.

In most cases however, the A and B-sample results are identical and traces of cocaine, known as benzoylecgonine, can be detected in urine for several days after taking the drug - meaning it would have been taken at some stage during fight week.

Parker (36-4, 24 KOs) is said to be currently on holiday, and while eager for redemption after his latest defeat, his manager David Higgins told The Ring post-fight there was no expectation on his charge to return for a 'little while' before this development.

The VADA will now handover their findings to UKAD and the British Boxing Board of Control, who oversee doping and punish offenders.

Although cocaine is a recreational drug and not performance-enhancing, the Kiwi could potentially face a two-year suspension.

A Queensberry Promotions statement read: "The Voluntary Anti-Doping Association last night informed all required parties that Joseph Parker returned an adverse finding following an anti-doping test conducted on the 25th October in relation to his bout with Fabio Wardley.

"While the matter is investigated further, no additional comment will be made at this time."