Mr Bruce and his mates stayed out in the surf - until they realised the shark was still there.
"He got pretty freaked out and caught the next wave in," Mr Bruce said. "Then the shark came around again and gave my mate a nudge on his board. Then it came and bumped my board, quite hard."
Mr Bruce said the shark was about 1.5m to 2m long and he thought it could have been a great white or a bronze whaler.
Once all the surfers were back on shore, they realised Mr Garrett had a nasty bite in his calf.
"He was bleeding quite a bit. I had my work truck and all my gear, so we cleaned him up and sutured him. He was in shock from the incident."
Mr Bruce took a photograph of the gash in Mr Garrett's leg and said the damage could have been much worse and it was a scary experience.
He joked that the shark could be the Taranaki Terror - a large great white that hung around fisherman for several summers.
"We all heard about it, and laughed about it - but it's a bit different when you see one in the water for yourself. I thought, 'Jesus, what's going on?'
"It was a bit scary because there was a bit of blood in the water and it could have caused a feeding frenzy."
Mr Bruce thought others should be careful in the water, but should also remember that the shark had more right to be there.
"We're in their environment. It's their natural habitat, we haveto respect that."
Department of Conservation marine scientist Clinton Duffy said that without a more specific description it was hard to tell what sort of shark bit Mr Garrett.
"Other than to say it seems unlikely it was a great white shark because the guy still has his leg.
"He was unlucky to get bitten, but lucky to survive."
Mr Duffy said shark bites were uncommon in New Zealand.
The last death from a shark attack was in Whangamata in 2010.
