Richard Townley, 34, of Wellington, had been contacted before the closing date but he declined an interview, saying he wasn't able to speak yet.
The two others in the line-up Jo Hayes, 55, of Apiti, and Alastair Scott, 44, of Wellington, were profiled, before the closing date.
Eketahuna-born farmer and list MP Mrs Hayes, no relation to incumbent Wairarapa MP John Hayes, came into the Times-Age office in February, offering to be interviewed.
Last year, Matahiwi winery owner Mr Scott put his name forward saying Wairarapa needed fresh representation.
John Hayes announced his retirement earlier this year.
Bernard Cleary, National's Wairarapa electorate chairman, said the candidates were following the rule to make sure they got through the selection process.
The party's general manager, Greg Hamilton, said the rule was there because the selection was by party delegates, not the public.
"It's really because it's an in-house selection process," he said. Mr Hamilton said the nomination was going to be keenly contested.
The person selected will be named on April 25.