Christchurch Airport chief executive Malcolm Johns said the service offered more than 70,000 seats and an estimated more than $100m in visitor spending for the whole economy.
"That is positive news not only for the tourism industry but also for southern air freight needs, which add up to significant economic development opportunities for every region of the South Island.
Government statistics showed that when the entry point is Christchurch every South Island region benefited because visitors on average leave around 85 per cent of their spending in the South Island. This drops to less than 35 per cent when the entry point is not Christchurch, said Johns.
Despite cooling growth in China and a share market slump, China Southern is also increasing flights to Auckland moving to double daily year-round from October.
The airline is that largest in Asia, in terms of fleet size as well as the number of passengers carried.
China is New Zealand's second biggest market for tourists behind Australia.