A man has been airlifted to Royal Perth Hospital with apparent leg injuries after he was bitten by a shark near Gracetown.
The hospital where the victim was taken says the man's condition is stable.
A shark attack at Cobblestones Beach near Gracetown, WA, put the event at Margaret River on hold.
Event organisers put the competition on hold but have not said whether the victim was taking part in the competition.
Australia's two-time world champion Tyler Wright and Kiwi Paige Hareb were the first surfers to hit the water for their round-two heat after the shark scare.
In a statement posted to its Facebook page following the incident, the WSL said it had chose to suspend the competition for an hour after "discussions with local authorities".
"Further enhanced safety measures, including ski and drone presence, will be added to the event's mitigation protocols".
"We have been alerted of a shark incident that occurred near Gracetown", the WSL said in a tweet. The safety of our surfers & staff is a top priority.
Surf photographer Peter Jovic was on the beach and witnessed the surfer being mauled by the shark, ABC News reported.
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"If anyone is familiar with the Mick Fanning moment.it was very similar to that, where a shark pretty much popped up and ended up knocking a surfer off his board", Jovic told Australian Broadcasting Corp. radio. "After that it was hard to see what was going on".
Mr Newland said the man was conscious the whole time.
Channel Nine reporter Michael Stamp said the man did not realise the beach was closed.
Fisheries scientists from Department of Primary Industries and Regional Development will inspect the surfboard that was being used by the injured surfer.
A shark attack on a surfer in Australia has forced the temporary suspension of an global surfing competition. Chris Boyd, 35, was killed at nearby Umbies surf break in 2013.
"It was a large shark and from the way it was behaving, it would have been a white pointer".
All three were surfers.