Francois "The White Buffalo" Botha was left fuming after he lost to Sonny Bill Williams on points in their WBA International heavyweight bout in Brisbane, Australia.

Cut short from the original 12 rounds to 10, Williams looked in control for most of the fight.

The South African, however, was furious with officials after the decision was made to shorten the bout, with the 44-year-old looking to have worn out Williams by the end of the 10th.

"You know I love Sonny Bill, I think he's a great guy, a gentleman, but this was bullshit," the 115kg Botha said in an interview after the fight.

"If you look at the crowd, you know who won. You've got to win fair and square, not with the advantage of the judges, you've got to fight. According to me I won, hands-free."

Botha's trainer, Hardy Mileham, was shocked to see the bout shortened --a decision that was seemingly made during the contest.

"The fight was scheduled for 12 rounds, and in round number 10 he (Williams) was in danger," Mileham said.

Despite a strong comeback by Botha in the final stages, with Williams visibly shaken, it was ultimately not enough to sway the judges.

Botha, who did not sit down once between rounds, came out firing in the final round, nearly bringing Williams to his knees with a flurry punches.

Over the first four rounds Williams, 27, had dominated proceedings, while Botha clearly adopted a strategy of outlasting his younger opponent.

The veteran South African taunted Williams throughout the early rounds.

With a number of powerful left-hand jabs, Williams caused Botha's right eye to close up.

Botha said he wanted a rematch against the New Zealand heavyweight champion and All Blacks rugby star.

"A rematch -- if he can beat me he can go on, but if he doesn't he should throw in the towel."