Unfortunately, when the two men were brought to shore, the Chinese man was unable to be revived and was pronounced dead at the scene, police said.
The Taranaki Rescue Helicopter was called to the scene, along with Surf Lifesaving and Coastguard.
The survivor, in his 60s, suffered from minor hypothermia and was treated by ambulance staff at the scene.
"There is no doubt the surfer saved the life of the other man who was in the boat when it overturned," Senior Sergeant Thomas McIntyre of New Plymouth police said.
"His actions are commendable and we are continuing to speak to him and other witnesses in an effort to piece together the sequence of events."
Neither of the two men were wearing a life jacket at the time the boat overturned, police said.
They would not release the name of the deceased man until formal identification was completed, and his next of kin had been informed.
Tukaha Ashby, 12, and Heydon Healey, 35, of Waitara, were among numerous others who arrived at the Waitara River mouth late this afternoon to surf, walk or just watch.
Surveying the deceptively calm entrance to Waitara River, the scene of today's drowning, they said they were shocked but not surprised at news of the tragedy.
"The bar across the mouth has come up about a metre since the last big flood a month ago," Mr Healey said.
Boaties who didn't know where the channel is were often seen coming straight over the bar, some of them hitting it.
Surfers from the Waitara Surfboard Riders Club said four or five boats had rolled on the bar in recent years.
They said it was safe to cross a couple of hours either side of high tide if the channel was used. However, it moved around from time to time when storms hit the coast.
They said there was a big surf running at high tide today.
Maritime New Zealand spokesman Steve Rendle said it was recommended that everyone wore the right sized life jacket, at all times, while on a boat.
"This is obviously a tragic accident, and our sympathies go out to the family of the person involved."
Mr Rendle said it was important boaties were always prepared with the appropriate tools when on the water, whether that was a life jacket, or a way to communicate with appropriate services if an emergency occurred.
He said it was also important for people to be aware of the conditions, especially when it came to bar crossing."
Make sure you've talked to locals so you know what the conditions are going to be like, Coastguard are a good source of information about bar crossing. Just be aware of the conditions you are going into."
According to the law, everyone on a boat had to carry a life jacket, Mr Rendle said.
"Some local authority by-laws require that it be worn at all times... our advice is you should wear a life jacket. When something goes wrong you don't want to be scrambling around thinking where is my life jacket."Putting a life jacket on when you're already in the water is not easy."
