Northland's new National candidate is Doubtless Bay business owner and council employee Mark Osborne from Taipa.
Voting at Saturday's selection meeting had to go to a fourth round before Mr Osborne had an absolute majority of ballots cast by the party's 118 Northland delegates.
Four other nominees made it to the final shortlist - Mita Harris, Matt King, Grant McCallum and Karen Rolleston - with the delegates' final choice a tight three-way race.
The Advocate understands the final ballot was between Mr Osborne and Mr McCallum, a Maungaturoto dairy farmer. Matt King, an Okaihau farmer and fraud investigator, was eliminated one round earlier.
About 150 people attended the selection meeting at Kerikeri Sports Complex.
Mr Osborne wasted no time after his selection, immediately taking leave from his job as Far North District Council asset manager and an hour later hitting the campaign trail at Kerikeri's Ocean and Orchard Festival.
Mr Osborne said he was very pleased to have won the delegates' confidence and paid tribute to the other nominees. All were staunch National people with bright futures in the party, he said.
He suspected his combination of business and local government experience had given him the edge.
Among his priorities, if elected, would be helping to push through reforms of the Resource Management Act.
National was not taking the byelection lightly and would "throw everything into the campaign," he said.
In the March 28 poll Mr Osborne will go up against NZ First leader Winston Peters, Labour's Willow-Jean Prime, Mana's Rueben Taipari Porter and Act's Robin Grieve. The Green and Maori parties are not standing.
The byelection was triggered by the sudden resignation, for "personal reasons", of Northland MP Mike Sabin.
Mr Osborne has previously managed Kaitaia's Te Ahu Centre and co-owns Doubtless Beauty with his wife Jodi. They live in Taipa and have two children.
Mr McCallum was believed to have been favoured by the National Party caucus as Mr Sabin's replacement, but is not well known in the Far North where most of the delegates are based.
Ms Rolleston is believed to have performed well at selection meetings but counting against her was the fact she lives outside the electorate in Helensville.