"It's about giving our kids, and their kids to come, a place to call home.
"Our Government believes that housing is at the heart of what makes communities strong. Everyone deserves to have a warm, dry and affordable home."
Ardern said it was fitting to welcome the families into their new homes on the first anniversary of the formation of the current Government.
"It's incredibly heart-warming," she said.
Twyford said the Government was committed to tackling the national housing crisis.
"And the terrible impacts on families of unaffordable housing and a rental market under pressure," he said.
"These 18 families today make KiwiBuild a reality. This is just the beginning.
"We busy building more KiwiBuild houses throughout the country.
"We're also making housing more affordable by banning overseas speculators and closing tax loopholes, and reforming the rental market."
Twyford said there was still a lot to do to "build our way out of the housing crisis".
"But today shows the progress we are already making," he said.