"Where in the rule book does it say Santa has to be big, fat and in a red suit?"
It was Hollywood and John Sands that had created Santa into a big frame, he said.
"The historical St Nicholas was tall and slender."
He was also aware that some children were traumatised by the "big, fat man".
However, not everyone was on board the same sleigh. A grandmother called the Chronicle, objecting to the new-look Santa and said her grandchildren thought he was "stink".
And another woman called, protesting strongly and stating if she had children she would not be taking them to see the centre's Santa.
Seventeen-year-old Jay Duggan is the Kiwi Santa, wearing a bright-coloured red shirt, sunglasses, jandals but with the traditional white beard and hat. With him on his "merry round" are his cheerful helpers, Ronan Heathate, 14, and 16-year-old Tangihaere Gardiner.
By 3.30pm yesterday, Facebook comments were leaning in favour of Kiwi Santa.
Danielle Bourne was delighted with the "new look".
"There is nothing like a Kiwi Christmas, so why not have a Kiwi Santa? I love the idea, and so will the little kids. We don't need to be traditional, we only need to be us. This is fun and a great idea, so stop trashing it."
Others online were unimpressed: "Seriously Trafalgar Square, how many Santas have you seen that have been skinny and oh about 15 years old?" asked one.
Others were also decidedly chilly: "That's not Santa, I can see many disappointed wee children who have seen pictures of Santa , then are very disappointed with what they see in your square NOT COOL."
However, Santa left his comment on Facebook yesterday to say that he had seen the "kids' faces light up".
"A lot of the older [teenagers] obviously knew but the younger ones loved it and it's all about the smiles on their faces when they leave from Santa.
"I love doing this job just to see the smiles on the kids' faces. Would you rather see a smile on your kid's face or no smile at all because there was no Santa? I know which one I would choose."
Yesterday, Kiwi Santa ran out of candy canes but Mr Whittaker said he was restocked in time for the afternoon shift.
Kiwi Santa will be at Trafalgar Square daily from 10am-2pm and 4-6.30pm until Christmas Eve.