China became New Zealand's number one export destination in the March quarter, official data showed Friday, displacing Australia from a position it has held for decades.

Statistics New Zealand (SNZ) said the export of goods to China was worth NZ$2.3 billion ($2.0 billion) over the three-month period, up 34 percent on the same quarter last year, consisting largely of dairy products, timber and wool.

In contrast, exports to Australia slipped 7.3 percent to NZ$2.2 billion over the same period.

"China became New Zealand's top export destination in the March 2013 quarter, overtaking Australia for the first time," SNZ said.

"Twenty percent of goods exported went to China, compared with 15 percent in the same quarter of the previous year."

Exports to China have ballooned since New Zealand became the world's first developed country to sign a free trade agreement with the Asian giant in 2008.

However, the data released Friday related to goods only. Australia remains New Zealand's top trading partner if both goods and services are taken into account.

Two-way trade between New Zealand and Australia was NZ$17.7 billion in the year to June 2012, compared to NZ$13.8 billion for trade with China, according to official figures.

Wellington and Beijing have agreed to try to lift two-way trade between the two nations to NZ$20 billion by 2020.