On current polling, Seymour would be joined to two or three more Act MPs.
Van Velden has been a parliamentary adviser to Seymour and helped to organise to the passage of the End of Life Choice Act, which will put to voters as a referendum at the September 19 election.
Seymour said Brooke van Velden was qualified in international trade.
Her private sector experience as a corporate affairs consultant and political experience at Parliament had given her a deep understanding of the economy and the effect big government policies and rushed laws have on businesses and individuals.
Van Velden said she switched from being a Green Party voter to an Act supporter while studying economics and international trade at Auckland University.
"The ability for free markets to lift countries from hardship was a revelation for me."
Nicole McKee was a small business owner having delivered firearms safety education in rural and isolated communities for New Zealand Police.
She had a background in law, firearms component imports, was the coordinator of the nation's volunteer firearms safety instructors for the Mountain Safety Council as well as being the spokesperson for the Council of Licenced Firearms Owners and its Fair and Reasonable Campaign.
McKee said she would be campaigning to raise Act's Party vote in Rongotai.
"I do not believe that emotive and rushed legislation that adversely affects those it is intended to support is viable.
"Our laws should be rooted in policies that recognise our democratic rights to think, to speak and to behave in a legal and unobstructed way."
Chris Baillie, a secondary teacher and former police officer, is at No 4. He also owns a bar in Nelson employing 30 people.
Simon Court, an engineer, is ranked at No 5 and will stand in Te Atatu. He said his youngest son has Down Syndrome and he intended to take a disability perspective to Parliament.
Act president Tim Jago said the calibre and experience of candidates would impress people from every persuasion.
"We have candidates from all walks of life - people who have built their homes, families and businesses and who want to protect and enhance our free society. Our candidates will bring a strong dose of common sense to Parliament," he said.
Among the candidates were End of Life Choice advocates, a former police officer, two teachers, two lawyers, three farmers, four engineers, eleven business owners, and 13 licensed firearms owners.