New Zealand rugby star Sonny Bill Williams will fight South African Francois Botha in Durban on November 17, a promoter said Saturday.

After months of media speculation about rugby off-load maestro Williams boxing in the republic, promoter Thinus Strydom said arrangements for the bout were concluded this week.

Williams, who played for the All Blacks against Australia on Saturday in the opening match of the new Rugby Championship, is the reigning New Zealand Boxing Association heavyweight champion.

The 27-year-old, who helped Waikato Chiefs win the Super 15 title for the first time this month, is quitting New Zealand soon to play rugby union in Japan and later rugby league in Australia.

Botha, a 43-year-old known as the 'White Buffalo', has won 48 fights, drawn three and lost seven and his previous opponents included American Mike Tyson, Briton Lennox Lewis and Ukrainian Wladimir Klitschko.

Quizzed this year about a possible fight against Williams, Botha told South African newspaper Rapport he would not mind doing it "somewhere during half-time of a rugby match" with "one hand tied behind his back".