Corrections Minister Judith Collins has announced she will run for the Prime Minister's job this afternoon.
Collins delayed making an announcement after a National caucus meeting this morning, saying she was still "taking some soundings" and that she was gauging her levels of support.
She has now confirmed that she will stand.
Collins has been in Parliament since 2002, representing National in the Clevedon and Papakura seats. She was previously the most senior woman in Cabinet but was demoted in 2014 after she was alleged to have undermined a senior public servant while serving as Police Minister.
Collins made her comeback last year, taking on the corrections and police portfolios.
Deputy Prime Minister Bill English and Health Minister Jonathan Coleman have already entered the leadership contest.
Collins said the leadership position should go to the "best person for the job".
But she also underlined the different approach she would bring as a woman candidate, saying the National Party leader needed to connect to both men and women, as well as all ethnicities.
"And I believe I can do that."
She said National had been led by men "for quite some time".
While she did not directly address English's poor election result in 2002 when he was party leader, she suggested she would be the better choice to win an election.
"I would not be putting my name forward if I didn't believe that I would have a very good chance at leading us into victory in 2017.
"And that's what this is all about. It is about who can deliver a National-led Government, do whatever deals that are needed in terms of MMP to deliver that, and I believe I can do that."
Collins said she had not chosen a potential deputy leader.
Collins also believed she could overcome her past controversies, claiming she had been "completely exonerated" and was "happy to move on".
Collins was stripped of her ministerial portfolios in 2014 after it was alleged that she undermined the head of the Serious Fraud Office Adam Feely while she was Police Minister. Following an inquiry, she was restored to Cabinet in 2015.
She also faced accusations of a conflict of interest after she visited the Chinese office of milk exporter Oravida while on Government business. Her husband is an Oravida director.
"One of the things that you learn in life is that you learn from things that go wrong.
"I've learned an awful lot."
Collins said the 2017 election campaign would be the "toughest campaign ever" for National.
"And I know that we need to win. And the only way we can do that is if we have some of the toughest people running it."