Key Points:

Patrons at a free family Christmas concert have been left as red-faced as Santa's suit after hearing what they thought was profanity from the mouth of Father Christmas.

It seems Santa thought he was saying "thank you" in Norwegian, but all that some members of the audience could hear was "f***!"

About 1600 people, including the New Zealand head of the Mormon Church, attended the Auckland Symphony Orchestra's free family Christmas concert at the Auckland Town Hall last week.

Elves scattered sweets for children while the orchestra played, joined by several choirs, including those from the Church of Jesus Christ of Latter Day Saints and Greyfriars Presbyterian Church.

A woman in the audience said it was an "absolutely lovely occasion" - until, she said, Santa swore. She was absolutely certain Santa said f***. The audience was almost silenced, she said.

"It annoyed me. It soured a very nice occasion. People took exception to it. It was very inappropriate."

Ron Lauese, Greyfriars Presbyterian Church community minister and conductor of the church's choir, said he also thought Santa had sworn, but realised Santa had not set out to be inappropriate. He had not been offended.

"He has an accent. I think people mistook it and got confused. I think in his accent he's tried to say something and it has been misunderstood to mean something else," said Lauese.

Auckland Symphony Orchestra musical director and conductor Gary Daverne said on Thursday that he thought Santa had actually said "tuck". "We didn't have any control over that," he said.

"It came as a bit of a surprise. It was bad diction... I was taken aback," said Daverne, who planned to have a chat with Santa and advise him "to be careful of what words he chooses in future".

However, on Friday Daverne said he now knew that Santa had said "takk"- which is "thank you" in Norwegian.

Daverne would not reveal Santa's identity, saying only that he was an 84-year-old father of one of the orchestra members and grandfather of several elves and fairies at the concert.

He had been active in the music world for a long time and used to manage youth orchestras. He was a "wonderful man".

Daverne offered to contact the woman who was offended to "smooth things over" and so he could send her a letter of apology.

The Christmas concert was a huge success, he said, enjoyed by everyone who saw it and the annual event should be celebrated. No one had complained to him.

The paper's source agreed it was a fantastic event and Daverne's orchestra was superb. However, she wanted "something to be said" about the incident so it would not be repeated.