Kelt Capital owner Sam Kelt, a former boxer, confirmed his sponsorship, saying the decision was an easy one as the proceeds were going to "a great cause".
Hawke's Bay Magpies halfback Chris Eaton and his brother, Kim, are organising the event as a fundraiser for the Jarrod Cunningham Trust and Kim's Auckland-based 9-year-old niece, Lili, who was diagnosed with a brain tumour when she was 5.
Last year Lili was chosen by the Make a Wish Foundation and Team New Zealand to present the Duchess of Cambridge with a posy of flowers before she went sailing in Auckland.
Mr Kelt said he was touched by the compassion for Lili Reynolds and her illness and said the community had shown extraordinary support for her. He said he didn't question his decision to sponsor the fight night despite the controversial inclusion of Mr Barber.
"I don't tend to be put off by controversy. I think all these guys are doing this for the right reasons," he said.
Organisers expect a crowd of about 800.