China has urged New Zealand Prime Minister John Key to exercise "discretion" during his visit to China that started Sunday — an apparent attempt by Beijing to wield its considerable economic leverage in its dispute over the contested South China Sea.

In an editorial published Sunday by China's official Xinhua News Agency, Beijing said the focus of the trip by Key should be "more on economic ties and less on the South China Sea issue," which it said "is of no concern for Wellington."

Highlighting the importance of Oceanian countries, Xinhua touted China's economic ties with New Zealand — the first developed nation to sign a free trade deal with Beijing — but noted that relations between the two countries "haven't been entirely rosy" recently.