South Africa’s Bongi Mbonambi has been accused of using a racial slur towards England flanker Tom Curry during his side’s Rugby World Cup semi-final win.

Curry approached referee Ben O’Keeffe about half an hour into the match, reported the alleged comment and asked what he should do in response.

“Nothing please,” replied O’Keeffe.

England have 36 hours after the final whistle to refer such incidents to the citing commissioner, who could then call a disciplinary hearing.

With Saturday’s match kicking off at 20:00 BST, the deadline for England to report back to World Rugby is on Monday morning.

Curry was asked after the match whether something untoward had been said to him by Mbonambi.

“Yeah,” he replied, before adding that “it does not need to be talked about”.

It appeared that Mbonambi refused to shake Curry’s hand at the end of the match as the acrimony between the two sides continued after the final whistle.

SA Rugby – the South African rugby union – has started its own investigation into Curry’s claim.

“We are aware of the allegation, which we take very seriously, and are reviewing the available evidence,” it said.

“We will engage with Bongi if anything is found to substantiate the claim.”

Mbonambi is the only specialist hooker in the South Africa squad after the Springbok management opted to replace the injured Malcolm Marx with fly-half Handre Pollard earlier in the tournament.