Containers are piled at a port in China. [File photo]

China swung back to mark a trade surplus in March from February's deficit of 31.48 billion U.S. dollars, posting a 670-million-U.S.-dollar trade surplus in the first quarter, the General Administration of Customs (GAC) said Tuesday.

The country's foreign trade in March rose 7.1 percent year-on-year to reach 325.97 billion U.S. dollars, with a trade surplus of 5.35 billion U.S. dollars in the month.

Exports amounted to 165.66 billion U.S. dollars in March, up 8.9 percent year-on-year, while imports reached 160.31 billion dollars, the GAC data showed.

For the first quarter, China's imports and exports expanded 7.3 percent from a year ago to reach 859.37 billion U.S. dollars, with its foreign trade with major trading partners growing in single-digits, according to the GAC.

"Compared with foreign trade elsewhere, China's imports and exports were relatively good in the first quarter," said Zheng Yuesheng, head of the statistical department of the GAC.

However, Zheng said China's foreign trade had grown at pace much slower than a year earlier, underlying existing downward pressure for the country.

The 7.3-percent growth of imports and exports in the January-March period this year marked the slowest level since the fourth quarter of 2009.

The market widely expected China to record a quarterly trade deficit at around 5.4 billion U.S. dollars in the January-March period.

"The March growth in China's exports beat my anticipation, while import growth was lower than what I had anticipated," said Liu Ligang, director of the economic research department of ANZ Greater China.

He said the latest customs data suggested the external environment may have started to improve for China since March, as export growth accelerated to 8.9 percent in March from about 7 percent in the January-February period.

As China reported its first quarterly trade deficit in seven years during the January-March period of 2011, Liu said, the trade surplus in the first quarter of this year means the contribution of exports to the country's gross domestic product (GDP) would be positive.

"So, the GDP data for the first quarter might be higher than expected," Liu said.

Returning to a trade surplus underlined a string of economic indicators that the market is closely looking for clues about the health of the world's second-largest economy.

The National Bureau of Statistics (NBS) is set to release GDP data on Friday, and many institutions have projected that China's GDP growth will be around 8.4 percent in the first quarter.

The Consumer Price Index (CPI), a main gauge of inflation, shot up to 3.6 percent in March from a 20-month low of 3.2 percent in February.

The narrower trade surplus signalled that the exchange rate of the Chinese currency, the Renminbi or the yuan, was moving closer to a balanced level but the fluctuation will be more volatile on capital flow, Liu said.

Despite the lingering debt crisis, the European Union remained China's largest trading partner in the first quarter, but China-EU bilateral trade growth slowed to 2.6 percent year-on-year to reach 126.87 billion U.S. dollars, a development customs officials said need to pay attention to.

Zheng said he was confident that China will be able to realize 10-percent growth in imports and exports this year.

In the first three months, China's trade with the United States -- its second-largest trade partner -- increased 9.3 percent year-on-year to 106.77 billion U.S. dollars, according to the customs data.

The 10-member Association of Southeast Asian Nations (ASEAN) held its position as China's third-largest trade partner, with China-ASEAN bilateral trade amounting to 86.78 billion U.S. dollars, up 9.2 percent year-on-year.

Japan, which is still struggling to recover from last year's devastating tsunami and massive earthquake, posted a year-on-year decline of 1.6 percent in bilateral trade with China in the first quarter, or 79.44 billion U.S. dollars.

However, China's trade with Russia, which joined the World Trade Organization this year, showed rapid growth of 33 percent year-on-year, hitting 21.49 billion U.S. dollars.

Meanwhile, China's trade with Brazil, a major exporter of iron ore and other raw materials, gained 11.5 percent from the previous year to hit 18 billion U.S. dollars in the first quarter.

According to customs data, China's iron ore imports rose 6 percent from a year ago to 190 million tonnes, with an average import price down 13.4 percent to 137.1 U.S. dollars per tonne.

Soybean import volume went up 21.6 percent to 13.33 million tonnes, with the average import price dipping 8.2 percent year-on-year to 525.7 U.S. dollars.

Moreover, China imported 294,000 vehicles in the first quarter, up 24.9 percent.

Machinery and home appliance products led China's exports in the period, with a year-on-year increase of 9.1 percent to reach 252.99 billion U.S. dollars.

In the period, China's exports of garments, textiles and footwear reached 29.5 billion U.S. dollars, 20.44 billion dollars and 9.08 billion dollars, up 3.9 percent, 1.4 percent and 2.8 percent, respectively.