Australia's first heavyweight boxing champion, Lucas "Big Daddy" Browne, has reportedly tested positive to a banned substance.

ESPN has reported Browne tested positive to clenbuterol in a test conducted by Las Vegas agency Voluntary Anti-Doping Association (VADA) before his WBA bout with Russia's Ruslan Chagaev in Chechnya.

The reports say Browne's A-sample tested positive, but no testing has been done on the B-sample because VADA is demanding Browne pay for the second test.

A letter obtained by ESPN written by VADA president Dr Margaret Goodman to the organisers of the Browne-Chagaev fight read: "This letter is to advise you that the 'A' sample urine specimen number 2998060 collected from Lucas Browne ... has been analyzed for anabolic agents, diuretics, beta-2 agonists and stimulants.

"The results of the analysis are as follows: Adverse. Urine specimen contains Clenbuterol.

"Mr Browne has the right to promptly request analysis of the 'B' sample at his expense."

Clenbuterol is used as a metabolism booster to help burn fat.

Browne, who had to dig deep to overcome a disastrous sixth round and wobbly start against Chagaev, improved his record to 24-0 (21 KOs), while Chagaev dropped to 34-3-1, 21 KOs.

It meant Browne won the so-called regular version of the WBA belt, while Britain's Tyson Fury is considered the WBA's "unified" champion, since he also holds the WBO/IBO versions.

Browne's title promised much with the prospect of potential mega-fights against Fury and David Haye now very much in doubt.