By SABC Sport
17th October 2023
Australia's Angus Gardner will charge of the first semi-final between Argentina and New Zealand on Friday.
O'Keeffe also oversaw the Boks' epic showdown with France over the weekend, which left some French players, pundits and fans less than happy with his performance.
Springbok head coach Jacques Nienaber felt the Kiwi did a good job, however.
"I thought Ben was good on the day. We played in such a way to try and take the referee out of the game," he said.
It will be the first RWC semi-final for both Gardner and O'Keeffe.
Gardner will be joined at the Stade de France by assistant referees Nic Berry and Karl Dickson, with Ben Whitehouse as Television Match Official.
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Assisting O'Keeffe at the same venue 24 hours later will be assistant referees Andrew Brace and Paul Williams and TMO Brendon Pickerill.
O'Keeffe will referee a Test between the Boks and England for the second time, having been in the middle for South Africa's 42-39 victory in June 2018.
World Rugby also confirmed that South Africa's Jaco Peyper wasn't considered for either after sustaining a calf injury during the quarter-final between Wales and Argentina in Marseille.
"Congratulations to all selected. This is a team effort, and the selection reflects the hard work of the group as a whole, and the encouragement and support they give each other," said World Rugby High Performance 15s Match Officials Manager Joël Jutge
"I would also like to pay tribute to Jaco Peyper, who has been ruled out through injury. He would have been in contention. We wish him a speedy recovery."