Mr Key said he offered a "really detailed and thorough" response to a question from a girl at Waiuku College about extending Maori Language Week.
The schoolgirl was in tears after Mr Key reportedly dismissed her question about extending the week, her classmate Trent Brown Marsh told the Sunday Star-Times.
The girl was considering taking time off school because she was so embarrassed after the Prime Minister said people would get "bored" if the initiative was extended, the paper reported.
"I did not say that. I'm actually pretty perplexed by the story," Mr Key told Breakfast this morning.
"When it's a week, there's an intensity that takes place. And it would get diluted ... if we had it over a month."
He said he "certainly would never give an answer" that would upset a student.
Mr Key understood the paper would not retract the story as it stood by Mr Marsh's interpretation of his comments.
A spokeswoman for Mr Key earlier said students may have misinterpreted his answer.
Meanwhile, Mr Key said he wasn't convinced more laws were the best way to tackle aggressive dog breeds.
Data released at the New Zealand Association of Plastic Surgeons annual scientific meeting showed there were more than 99,000 dog bites in New Zealand in the last decade, about 27 a day.
Mr Key told TV One there was a risk tighter regulations would burden only registered dog owners, most of whom were very responsible.
"70 percent of dog bites occur in the family home, or with friends," he said.
The Prime Minister said it was possible many dog bites were a result of irresponsible dog owners who disobeyed existing laws.
But he hinted at a possible review of laws around dog breeds deemed dangerous.
