He spoke of the need for better transport links between Wairarapa and Wellington to further connect people and services.
"The [Rimutaka] road is passable, but it's a struggle."
Mr Key said developing the rail network would be the best option to get more people with expertise in the service sector to come to and from Wellington and Wairarapa.
"If we could speed it up there would be a lot more people commuting from Carterton and Greytown."
The Prime Minister also spoke of the need to stop effluent pollution in Wairarapa's waterways.
He said National had been working alongside Fonterra developing new science to try and stop leaching, but was also focused on getting the basics right such as proper fencing.
National's newly selected Wairarapa candidate Alastair Scott identified increasing population as a fundamental means of boosting the economy.
He talked about trying keep young people that go off to university close by encouraging Wellington or Palmerston North as options.
Mr Scott outlined the benefit of retirees settling in Wairarapa, which he said boosts spending and encourages service sector start-ups for others, as well as encouraging tourism "when the children and grandchildren come to visit".
He said the whole movement for a better economy in Wairarapa will start with a bigger population base.
"It's not just jobs, it's really people, people, people, and local people supporting local businesses."
Mr Scott talked about businesses in Wairarapa that didn't necessarily "have to be here" but were here because Wairarapa people encouraged them to be.
He mentioned businesses such as Breadcraft, Premier Beehive Bacon, and Parkvale Mushrooms.
Mr Scott said the key to businesses succeeding in Wairarapa was focusing on export markets.
"It's all about finding markets. Making it [the product] is easy, it's all about exporting."
He said the next thing Wairarapa people could do to help this process was to identify potentially growing businesses and inject capital into them.
Mr Scott said the Wairarapa irrigation scheme, of which he has been a supporter for 15 years, is the link between encouraging people to the region and creating jobs.