Fraser Penman, from Perth, was knock off his board by the beast while out at popular surfing spot Injidup beach in Yallingup, the same stretch of coastline where 25-year-old Matthias Bache went missing after cliff diving in March.

And following his close encounter, he took to Facebook to confirm he was unharmed, thanks to his younger brother Logan Penman.

"Encountered my first and last Shark attack today down at Carparks Injis!" he wrote. 

Although the species of the shark is unconfirmed, Surf Lifesaving WA tweeted earlier on Monday to say the shark may have been a great white. 

The same assumption was made by onlookers at the beach.

Vinnie Poller told WAtoday he was just minutes away from heading into the water himself when the shark attacked and he saw people scrambling back to the beach.

"I wasn't in the water when it happened, I was just checking it [the surf] when I saw everyone paddling in and the guy's board broken up on the beach as he came ashore," he said.

"I don't know the guy and it's crazy that no one was hurt, but you just have to be thankful to walk away from things like that, and he seemed okay though.

"It all looked pretty scary in the moment. It does make you think twice about going back in the water, because his board showed the damage a white shark can do. But you have just got to accept that they are part of the ocean and we can't really do much about that."

A photo emerged shortly after the attack of Mr Penman's surfboad - near ripped in half - while another photo showed a makeshift warning sign made to alert other surfers of the attack.

"No joke. Shark attack. Big and aggressive," the homemade signpost read.

Further down south, another shark was spotted just 50 metres from shore at Kelp Beds Beach near Esperance.

There's been over 60 shark sightings off WA's coast in recent weeks with the Department of Fisheries even closing a stretch of coastline in Perth's northern suburbs over what it called "an unprecedented number of sightings over a sustained period of time and in a small stretch of water."

The Department of Fisheries said officers will conduct patrols there on Tuesday morning and continue to monitor the area.