South Korea's trade surplus contracted to 33.3 billion U.S. dollars last year due to external uncertainties such as Europe's debt crisis, but exports posted a record high helped by robust demand for ships and oil products, a government report showed Sunday.

Trade surplus reached 33.3 billion dollars in 2011, down from 41.2 billion dollars tallied in 2010, according to the Ministry of Knowledge Economy. As for December, the trade surplus stood at 4 billion dollars helped by strong exports and imports, reaching their monthly highs last month.

Exports showed a record annual high of 557.8 billion dollars in 2011, up 19.6 percent from the previous year. It was the first time the nation's export breached the 500 billion dollar mark on an annual basis. Imports grew 23.3 percent on-year to 524.5 billion dollars.

Helped by strong growth in both exports and imports, the country's trade volume rose above the 1 trillion dollar mark for the first time in its history. "Our trade slowed somewhat after August when external risk factors emerged, but our exports and trade volume breached the 500 billion dollar and the 1 trillion dollar marks respectively for the first time in our history," the ministry said in a statement.

The ministry noted that outbound shipments of locally-made ships and oil products showed outperformance last year despite Japan's deadly earthquake and political unrest in the Mideast nations, saying that the nation's growth of exports and imports slowed only slightly in the second half of last year despite the spread of the European fiscal crisis and the first-ever credit rating downgrade of the United States.

South Korea's trade surplus was expected to decrease to 25 billion dollars in 2012 due to growing uncertainties over the global economy, the ministry said.

Exports were expected to reach 595 billion dollars this year, up 6.7 percent from a year earlier, while imports was predicted to reach 570 billion dollars, up 8.7 percent from the previous year, according to the ministry.