The 45-year-old American, 11-times world champion, said on his Instagram account the "prognosis is now looking like 4-6 months recovery."

On Tuesday Slater posted a harrowing x-ray of the foot asking "You ever folded your entire foot backwards?"

"Kinda like smashing my foot with a big hammer as hard as I can. Sorta feels like I'm giving birth out of my foot right now," he said.

Having won the first round of the competition in South Africa, the accident happened on Monday.

"I pulled into a barrel (rolling wave) this morning and the whitewash bounced the board back into my foot as I hit the closeout, taking all the pressure into the metatarsals."