WELLINGTON, New Zealand (AP) - New Zealand boxing officials say allegations that former world heavyweight title contender David Tua used banned drugs are "pie in the sky" and demand supporting evidence or they be dropped.

The allegations, that Tua used a liquid formula containing the banned stimulant ephedrine to lose weight before bouts, including his November 2000 title fight with Lennox Lewis, emerged in court papers filed in New Zealand during an acrimonious legal dispute with his former manager.

Manager Kevin Barry, who lost to Evander Holyfeld in the heavyweight final of the 1984 Los Angeles Olympics, said in a seven-page affidavit that Tua knowingly used ephedrine as a weight loss aid from 1999, while living in the United States.

Ephedrine is listed as a banned substance by the World Anti-Doping Agency because it is performance enhancing.

Barry said Tua resorted to the drug when his weight ballooned above 300 pounds (136 kilograms). He said a Los Angeles-based biochemist designed a liquid delivery system which ensured the ephedrine was effective but did not show up in urine samples.

Tua admitted using a weight-loss formula he knew as thermo-fusion but said he did not know it contained a banned substance.

"If I'd known that stuff was a banned substance I would not have taken it," Tua said in response to Barry's allegations which appeared in a New Zealand newspaper on Sunday.

"I didn't know it as ephedrine. I only knew it as thermo-fusion."

Tua's manager, former All Black rugby player Inga Tuigamala, said the allegations were a sign of the bitterness and immaturity of his former manager Barry, and financial adviser Martin Pugh.

He said Barry and Pugh, who have been locked in a legal battle with Tua over management rights and assets, had set out to destroy the boxer's reputation.

New Zealand Boxing Federation chairman Gary McCrystal challenged Barry to prove his allegations or drop them.

"These are serious allegations. Barry should either lay a complaint with the police or shut up," McCrystal said on Tuesday.

He said as the alleged offending took place in the United States it would be a matter for that's country's justice system to pursue.

Barry has refused further comment.