Simon Bridges has been announced as the new leader of the National Party and Paula Bennett will stay on as deputy.
Mr Bridges said his job as leader will be to hold the Jacinda Ardern-Winston Peters coalition to account.
"Their Government is big on lofty intentions, but struggling to turn that into real gains for New Zealanders," he said.
"That's why we will continue to present an ambitious and strong alternative government, heading into 2020."
56 MPs cast their vote in a secret ballot for the last couple of hours at Parliament.
The caucus heard a five minute speech from each of the candidates before voting.
Amy Adams, Judith Collins, Mark Mitchell and Steven Joyce were all vying for the role.
Mr Bridges will replace Bill English, who will deliver his valedictory speech on Thursday and then leave Parliament for good.
Watch the announcement here:
Follow RNZ's live blog for all the latest developments and announcements: