Berlin - World heavyweight champion Manuel Charr has had to call off next week's title defence, and is set to be stripped of his WBA belt, after testing positive for steroids.

The 33-year-old, who was born in Lebanon but lives in Germany, was due to defend his title against American Fres Oquendo, 45, in Cologne on September 29, but the fight is off after Charr tested positive for two anabolic steroids.

"Under the circumstances, we will unfortunately have to cancel the world title fight," Charr told Cologne-based newspaper Express and his management confirmed the title defence was off to SID, an AFP subsidiary.

"I can only ask my fans and all the people in Cologne to believe me and to trust that everything will be cleared up.

"I'm totally shocked by the news - I have never taken anything."

Charr is set to lose the World Boxing Association belt he won last year, but Britain's Anthony Joshua is the WBA 'Super' champion and will defend his title in London on Saturday against Alexander Povetkin.

Germany's top selling daily Bild, Express and magazine Spiegel all report Charr tested positive for the steroids epitrenbolone and drostanolone.

"These are both anabolic steroids. That is absolute hardcore doping. In boxers, the emphasis is on increasing muscle strength," doping expert Fritz Soergel told Bild.

The 'B' sample will now be tested, but if they also contain the steroids then the future looks bleak for Charr.

"The fight is shelved. In my opinion, the WBA will take the belt off Manuel," Thomas Puetz, President of the German Professional Boxers Federation (BDB), told SID.

"Two substances were founds in one of Manuel's samples taken at a training camp on August 31, which have been on the banned list for some time."

Charr won the vacant WBA belt last November with a unanimous win against Russia's Alexander Ustinov and claimed to be Germany's first heavyweight champion since Max Schmeling.

It turned out to be a lie, because the Beirut-born son of a Syrian family does not own a German passport.

Charr's failed drugs test is the latest twist in a colourful career.

In September 2015, he was left fighting for his life after being shot in the stomach following an altercation at a kebab restaurant in Essen.

He returned to the ring just seven months later, bearing the scars of the attack on his abdomen, but another setback followed earlier last year when both hips had to be replaced.