Former Act party president Catherine Isaac has been confirmed as the number two on the party list.
In a joint press statement, party leader Don Brash and president Chris Simmons confirmed that all candidates would move one place up the list to fill the position vacated by the retiring John Boscawen.
Ms Isaac was widely tipped to be the mystery candidate, but needed to confirm her availability, depending on the health of her husband and head of the Business Roundtable Roger Kerr.
Dr Brash said Ms Isaac was highly respected and had the unanimous support of the party board.
She was the party president between 2001 and 2006, and is currently managing director of a communications consultancy.
Ms Isaac said in a statement she wanted to help ensure the Party remains true to its core principles,which are all about a stronger, more flexible economy and higher standards of living for all.
"New Zealand is facing the worst economic outlook since 1984. The Government needs to go further and faster and take some tough decisions to safeguard the country and put it onto a path to genuine prosperity. There are a lot of people out there who would like to see the government do that.
"I also see improving choice in education to better equip our young people for life as a vitally important area of focus, and as a former Welfare Working Group member I have a strong interest in welfare reform.
"But our key concern is the economy and that will be our strong focus going forward."