A 10-meter (about 33 feet) humpback whale knocked unconscious, Bishan Rajapakse, a 38-year-old Kiwi surfer at the Bondi Beach in Australia, according to media reports.

He was swimming at the southern part of the beach for about an hour before his friend, Chris, signalled him to come near him. It was only after moving towards his friend that Rajapakse saw the large whale.

Rajapakse, former Wellington doctor, told reporters that he remembered seeing the whale up close before the whale knocked him unconscious.

"Some other surfers were quite close to it and I remember wondering to myself about that tail - I thought 'Wow, this could just go and knock us all out'," he said, reports The Herald Sun. He was pulled to safety by the other surfers on the beach.

Rajapakse was treated at St Vincent's Hospital. According to local media sources, he had a slight headache and a sore shoulder and was released on Sunday.

Humpback whales are enormous (about 40 tons on an average) with large tails that enable to propel through water.

"His board had been smashed in pretty badly. It looked like he was thrown about three metres above the water. The tail of a whale is the strongest muscle on any animal in the world. Some humpback whales get up to 80 tonnes. It's an extreme no-no to go in the vicinity of a whale," said Anthony Carroll, lifeguard at the Bondi beach, reports stuff.co.nz. Carroll added that Rajapakse was about half a meter (about one and half feet) from the whale.