Mr Warren said boxing had become more popular in recent years with increased awareness of the sport's fitness benefits. Others were interested in the competitive side of the sport.
Williams' win was tarnished by allegations of poor sportsmanship amid confusion surrounding the length of the bout.
The TAB yesterday said it reserved the right to ditch the popular "Pick the Round" bet for specific bouts after it was forced to refund tickets following Friday's bout.
"Given Sonny Bill Williams was involved in two fights previously where the number of rounds was reduced without notice, we undertook all due diligence around the number of rounds for his fight with Botha," TAB general manager Martin Saunders said.
"So we are as confused and disappointed by what happened in Brisbane, as our customers are, given there was clear acknowledgment the bout was scheduled for 12 rounds."
However, Williams' manager Khoder Nasser said both camps knew the fight was intended for 10 rounds, although that was contradicted by Williams in the build-up to the bout, who said Botha would last the distance.
"He'll do 12 rounds pretty easy," Williams said on Thursday.
That was reinforced at the pre-fight weigh-in with an announcement the fight was set for "12 times three-minute rounds".
On Sunday, Williams wrote on Twitter that Boxing Queensland had acknowledged to both parties the fight was 10 rounds. He also said he had received a congratulatory phone call from the World Boxing Association.
However, New Zealand boxing coach Billy Graham described the match as an insult to the sport.
Graham, a former light welterweight boxing champion, told Radio New Zealand neither fighter should be boxing professionally.
He criticised their techniques and said Williams had no place in the ring. "It's just shame that he's got that sort of talent and he doesn't stick to his own sport and makes a mockery of ours. It makes it sound like anybody can just jump in the ring and do our game.
"There's consequences for it and he found out in that tenth round. He got some hard punches banged on him - if that guy [Botha] was 25 years of age instead of 45, he would have been flattened."
Both men had flouted the rules and embarrassed the sport, which was about "the art of self defence", Graham said.
It has also been reported Botha failed a drugs test before the fight.
The Sydney Morning Herald reported the 44-year-old submitted a urine sample on Tuesday last week, which revealed the presence of phentermine.
