The incident occurred as Mr Colville was enjoying the warm water.
"It was a beaut day and there were two or three porpoises out there and my mate goes, 'look there's a shark in a porpoise suit,' just being stupid.
"My feet were dangling in the water and I look around and there's this shark landed its head right on top of my board.
"I flicked it off and paddled hard to shore and my mate yelled out to 'keep paddling', he could see it following me.
"Luckily I caught a breaking wave heading in."
Some other people preparing to enter the water changed their minds when informed of the shark's presence.
"They had thought it was funny how we got out of the water so quick."
Mr Colville got a good look at the shark's head and described it as "brown, with white underneath and spotty, it was definitely not a blue shark".
"I didn't feel it hit, I didn't see anything, it just appeared.
"I've been surfing here probably about 23 years and I've seen sharks before but not where they try to bite my board -- I didn't expect that."
Mr Colville's friends saw the shark as it followed him and believed it to be a thresher shark -- identified by its distinctive tail fin.
Kahuna Boardriders Club cancelled their Learn to Surf lessons after the incident as a precautionary measure, but Mr Colville is relaxed about the encounter, saying "it's probably not here anymore, I'd say it wouldn't be hanging around.
One of the friends asked for the incident to not be "blown out of proportion" as he did not wish to "put people off the area".
Warmer sea temperatures in the Tasman have brought increased shark sightings off the Coast this year as well as plenty of sea mammals -- Tuesday was recorded at 21degC.
The thresher shark's distinctive tail fin is used to stun prey -- usually smaller fish -- before feeding on them.
On Tuesday Doc ranger marine reserves Don Neale said that DOC did not have a role in managing and monitoring sharks other than legally protected species, including white pointer, basking and whale shark.
"Thresher sharks are easily identified by their very long tail, and they're not considered dangerous to people."
- by Meg Fulford
