WELLINGTON -- China Eastern Airlines announced Tuesday it will start a year-round service between Auckland and Shanghai -- just a day after the two flag carriers of New Zealand and China detailed plans for direct connections from Auckland to Shanghai and Beijing.

China Eastern said its first-ever seasonal Auckland-Shanghai service, which ran from December 2014 to March 2015, had been so successful that it would run four times a week year-round from September.

"New Zealand is continuing to evolve in its popularity as a destination for Chinese travelers," China Eastern general manager Oceania Kathy Zhang said in a statement.

"We are excited to further grow our relationships in New Zealand and look forward to continued strong demand in this market. "

Auckland Airport said the service would add another 100,000 seats per year on the route, contributing an estimated NZ$122 million ($93.12 million) to the New Zealand economy.

"We have experienced great growth in Chinese visitors traveling to New Zealand during the peak season, with the 2015 Chinese New Year setting a record for Chinese arrivals to New Zealand," Auckland Airport general manager aeronautical commercial Norris Carter said in a statement.

"China is now New Zealand's second largest tourism market, with overall Chinese passenger arrivals increasing by 14.1 percent between 2013 and 2014," said Carter.

"As well as this, the growth in quality free independent travelers and group tours traveling direct from China to New Zealand, has seen Chinese spend in New Zealand grow to NZ$4,100 ($3,129) per visitor."

On Monday, Air China and Air New Zealand detailed an alliance that would see Air China introduce a daily direct service between the two cities, while continuing to codeshare on Air New Zealand's daily Shanghai-Auckland service.

Subject to regulatory approvals, alliance services could commence as early as December 2015.

Air New Zealand stopped its twice-weekly direct flights between Beijing and Auckland three years ago.