NSW Waratahs prop Benn Robinson has undergone surgery after damaging his jaw in a training mishap.

Robinson went under the knife after clashing with Wycliff Palu's knee during a contact session on Tuesday and won't be back to full training until February.

NSW head coach Ewen McKenzie witnessed the freak accident.

"It was a pretty heavy clash but in typical Benn Robinson fashion he still completed the tackle after the initial impact did the damage," said McKenzie.

"It's disappointing for Benn to have this happen just before Christmas but he'll return with the rest of the squad in January on a modified program."

Robinson had two plates inserted in his jaw and although his speech is unaffected he's had to adjust his food intake.

"I'm pretty much restricted to milkshakes and other types of liquids at the moment but otherwise I'm OK," Robinson said.

"These things happen in a contact sport and I can't wait to get back into full training."

The Waratahs squad, including Wallaby tour members, will assemble at Aussie Stadium on January 3.

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