An appeal has been lodged with the Nevada State Athletic Commission, declaring referee Russell Mora made a "clear error".

Moloney was certain he had reclaimed the title from Joshua Franco when the American was unable to take to the ring for the third round of their Las Vegas bout.

Franco's eye swelled up from what was ruled an accidental headbutt in the first round of the scheduled 12-round contest.

After the ringside physician ruled Franco couldn't go on at the end of second round because his eye was shut, the fight was called a no contest.

Commission officials reviewed the replay for a total of 26 minutes before upholding Mora's decision, which sent the boxing world into meltdown.

AAP has viewed the letter from Moloney's attorney, Josh Dubin, to the commission calling for the Melburnian to be granted a hearing to argue his case.

"The consequence of Mr Mora's erroneous determination of an accidental headbutt denied Mr Moloney the WBA Super-Flyweight World Title," Dubin wrote.

"Based on my experience interacting with both you and your team, I know that the NSAC wants to get this right not only for Mr Moloney's sake, but for the integrity of the sport."

Moloney, 29, couldn't hide his anger and frustration when the decision became official.

Promoter Bob Arum was livid about the decision, protesting to no avail to Bob Bennett, head of the Nevada commission.

Moloney told AAP on Sunday it was a heartbreaking pill to swallow.

""It's been a tough few months being away from my family but it would have made it all worthwhile to get my world title back," he said.

"When the doctor stopped the fight, I jumped up on the ropes and celebrated because I thought I had won.

"I'm just so devastated because it's something I have worked so hard for."

The bout was a rematch of their first fight when Franco knocked Moloney down in the 11th round and scored a unanimous decision over the formerly unbeaten Australian.

Australian Associated Press