The men, who Mr Miller thought were in their early 20s, were trying to make it back to shore but one had already started to become hypothermic and was getting into trouble, he said.
"One of them was very grateful [to be rescued] - he was pretty convinced he was going to drown."
One man was taken to Bay of Islands hospital around 6.30pm but his condition was not serious, said a St John spokeswoman.
Despite appearing grateful to Mr Miller, police said when they tried to talk to the men one of them ran away.
"He was uncooperative and unappreciative of officers' attempts to help him," said Inspector Ricky Whiu.