Land Rover Horse of the Year general manager Lauren Watson said the new event is not just designed for women.
"It's an all-inclusive chance for men and women to come along and hear the stories of some inspirational speakers," she said.
Mayor of Napier Kirsten Wise and Hastings Deputy Mayor Tania Kerr also reportedly plan to attend.
Green, who won New Zealand's first series of The Bachelor, said she looks forward to sharing an evening with fellow inspirational woman.
"As women, I think it's so important to lift each other up at every opportunity," she said.
"I'm passionate about helping others feel comfortable and happy in their own skin, through a few different approaches and I saw this as the perfect opportunity to spread that message even further."
Williams, who has represented New Zealand in show jumping and eventing, was left a C6/C7 tetraplegic after an accident in 2002.
The CatWalk Spinal Cord Injury Research Trust founder said she had to come to terms with a "new norm" after the life-changing injuries.
"So often through many tears I would say 'Why me?'," she said.
"The best thing you can do in life, whether it's work or play, is surround yourself with positive people, people who believe, support and back you."
The annual Land Rover Horse of the Year show attracts more than 50,000 spectators during the week of competition.
Ecoya general manager Claire Barnes said all of the women had given back to their communities in various ways.
"In this day and age we need women to inspire other women, raise each other up and be each other's champions - be it through charitable opportunities, business, sport, television or social media," she said.
"This panel of leading ladies will inspire others through their diverse industries and we're looking forward to hearing them all share their stories."
The annual Land Rover Horse of the Year show will be held between March 10 and 15 at Showgrounds Hawke's Bay Tomoana.
