British man Darren Mills, 28, was paddling off Porpoise Bay beach in the Catlins in early February when the three-metre predator pounced.
The shark clamped its jaws aroundMr Mills’ leg pinning him to his surfboard.
“I started punching it on the nose, a sensitive area for a shark, then got hold of its snout and tried to prise it off,” the air conditioning engineer told British tabloid The Daily Mirror on Monday.
“It must have been on my leg for four seconds but it felt a lot longer.”
When the shark let go, Mr Mills swam to shore with four huge bite marks on his right leg and a large puncture wound.
A friend used the board’s leash as a tourniquet and an off-duty paramedic and doctor assisted until a helicopter rushed him to hospital.
“I was scared,” Mills admits a fortnight after the attack.
“I got it into my head I was going to die from loss of blood.”
The 28-year-old, who lives in Queenstown, has been released from hospital but may need a year to recover fully.
“It (the shark) was incredibly powerful but I don’t bear a grudge,” he said.
“It’s not put me off surfing.”
In Australia, a contentious catch-and-kill policy is being trialled in Western Australia.
All great white, tiger and bull sharks longer than three metres caught on drum lines off the Perth and South West coasts are shot dead.
Shark attacks in Australia have fallen to their lowest level since 2008, according to University of Florida data.
Its annual International Shark Attack File found the 10 shark attacks in Australian waters in 2013 are the lowest annual total since nine in 2008, and are lower than the 12.3 average attacks per year during the past decade.
Australia’s two fatalities in 2013 are in line with its 1.4 yearly average over the same time period.