China and New Zealand have concluded a deal to upgrade their bilateral free trade agreement after three years of negotiation between the two countries.

The two countries released a joint statement announcing the conclusion of negotiations to upgrade the bilateral free trade agreement after a meeting between Premier Li Keqiang and Prime Minister Jacinda Ardern at the sidelines of the 14th East Asia Summit in Bangkok on Sunday.

At the meeting, Li said that China is very glad to see the completion of negotiations on the upgrading of FTA, indicating that the two countries are supporting free trade through direct action.

Ardern said the upgraded FTA will provide more opportunities for win-win cooperation from both sides.

"It reflects the importance both countries place on our relationship and builds on the significant mutual benefits both countries have enjoyed as a result of our excellent existing FTA," she said in a summary statement on the government of New Zealand website.

China is New Zealand's largest trading partner, with two-way trade recently exceeding $32 billion, according to the statement.