American Airlines will fly direct from Los Angeles to Christchurch three times a week from next year.
It is also launching a service from Auckland to Dallas.
The airline says the flights will launch in October 2020, and makes it the only carrier to take people direct from the United States to the South Island.
American Airlines senior vice president Vasu Raja said Christchurch was the gateway to the South Island, which summed up everything its customers were looking for in New Zealand.
The flights between Christchurch and Los Angeles will take 13 hours.
Christchurch Airport chief aeronautical and commercial officer Justin Watson said the service would turbocharge the New Zealand tourism industry and the national economy.
According to Christchurch Airport, the flights will bring an extra $52 million in visitor spenditure, with $40m going into the South Island.
Americans jetting into the country through Christchurch Airport spend 32 percent more and stay 34 percent longer than if they arrive elsewhere.
"This is a really welcome move ... we've actually had quite a patchy year with three airlines pulling out services from NZ, so this is terrific," Board of Airline Representatives executive director Justin Tighe-Umbers said.
The airline industry believed it was a saving grace for tourist numbers.
Tourism Industry Aotearoa chief executive Chris Roberts said: "North America is the strongest area for growth in visitation for New Zealand at the moment ... that's good news. We are in a slower growth period for tourism overall."
Air New Zealand recently revealed it will launch a direct Auckland to New York service from October next year.
The Air New Zealand service will fly three times a week.