Police officers were called to a shopping centre after complaints that school children were singing Christmas carols too loudly.
The children practising for next weekend's return visit to the centre
Ian Jones, head teacher at Ysgol San Sior, said 29 pupils were singing at Llandudno's Victoria Centre when security staff approached them.
Mr Jones described the request to stop or sing more quietly as "ridiculous".
The Victoria Centre apologised for the "upset" and said the situation could have been handled better.
The school had previously sung at the centre to raise funds at Christmas without complaint, Mr Jones said.
But, recalling Sunday's incident, he said: "We were asked to ask the children to stop singing otherwise the police would be called.
"The community support officer was already in the precinct and he was brilliant.
"He said that he wanted to join in with the singing because he thought they were so good."
Mr Jones said a compromise was reached by asking the children to sing a little more quietly, because "apparently it was competing with the sound of the tills."
He added: "I was expecting to see a candid cameraman jumping out and saying 'April fool' or something ridiculous like that because normally I tell the children to try to sing a bit louder.
"But to be asked to ask the children to stop singing or to ask them to sing a little bit quieter was ridiculous in my opinion."
Sue Nash, the Victoria Centre's manager, said: "We're really sorry that there was an upset and it could have been handled better, but we have taken steps to resolve the situation and look forward to hearing from the children again this Saturday."
A statement from the centre said it had always welcomed schools to sing, there had never been a problem before and the policy would continue in future.
It added: "There was a misunderstanding this year which has been resolved to the satisfaction of both the shopping centre and the school, who will be coming in again to sing this weekend."
Mr Jones confirmed he received an apology from the centre and that the children will return on Saturday as previously planned.