Joseph Parker and Santa are set to go head to head as the heavyweight title fight coincides with Auckland's Christmas in the Park.
Duco owner David Higgins predicts the audience for Coca-Cola's Christmas in the Park will halve on December 10, as the nation tunes in to watch Parker fight Andy Ruiz Jr at Vector Arena.
"We have a once-in-history event, which is truly unique and will capture the nation.
"I'd be worried if I was Christmas in the Park. It is a wonderful event but has been running a long time ... it happens every year. Many will choose the boxing as an historic moment."
Higgins compared the fight to the world heavyweight title bout between David Tua and Lennox Lewis in 2000, which he said stopped the nation.
More than 100,000 people attended last year's Christmas in the Park at the domain.
A representative for Coca-Cola Amatil took a less hard-line approach, saying he hoped both events were very successful.
"We are excited to have the heavyweight title fight in New Zealand.
"Christmas in the Park is the biggest, free family event on the calendar ... I'm not sure it will be affected."
The concert, which is in its 22nd year, has always been on the second Saturday of December, said the representative.
Audiences this year will enjoy in Christmas cheer with acts including Stan Walker, new screens that provide a 180-degree view of the show and 500kg of fireworks.
When it comes to transport the arena and domain are located just over 2km apart, which could see a hectic night on Auckland's roads.
The Coca-Cola Amatil representative said that was up to Auckland Transport to work out.
Duco will not change the date of the fight as a lot goes into organising an event like this, including scheduling with worldwide TV distributors, said Higgins.
"Santa would be well advised to visit Australia that night and come to Auckland the next week."
If Christmas in the Park is rained out it will be held the following day, on December 11.