By Agence France-Presse
Paul Kenny was riding the waves off Samurai Beach, a naturist spot 200 kilometres (125 miles) north of Sydney, when he accidentally clashed heads with the toothsome fish, reportedly a wobbegong or a bull shark.
"As soon as I did that he latched onto my arm and all I could do was punch it until it let go," Kenny, 50, told Sydney's Daily Telegraph.
"When I let go of it I saw its dorsal fin one metre away. I walked backwards as quick as I could and caught whatever wave I could."
A local ambulance service spokesman told AFP that paramedics treated Kenny for wounds to his upper right arm before he was taken to a nearby hospital.
Kenny said he was following in the footsteps of retired Australian surfing great Mick Fanning, who made global headlines when he fought off a shark on live TV while competing in South Africa in 2015.
"It's the Australian thing to do now isn't it?" Kenny added.
The latest encounter comes a month after two tourists were mauled in separate incidents at the Whitsunday Islands in Queensland state.
Experts say shark attacks are increasing as water sports become more popular and bait fish move closer to shore, although fatalities remain rare.