For the first time in 18 months, South Korean exports dropped last month.

The Ministry of Trade, Industry and Energy said Tuesday exports for April were tentatively estimated at 50 billion U.S. dollars, down one-and-a-half percent from the same period last year. 

The ministry pointed out that last April, shipbuilding firms exported offshore plants worth nearly five and a half billion dollars, causing a comparative surge in that month's exports last year.

Officials say the nation's exports are maintaining overall growth, citing that cumulative exports between January and April had surged six-point-nine percent compared to the same period last year. 

Exports of seven items saw growth, including semiconductors and petrochemicals while exports of ships shrank 75 percent on-year.

Imports in April amounted to 43-point-four billion dollars, up 14-and-a-half percent from the same period last year and posting growth for the 18th straight month.  

As a result, the national trade surplus was six-point-six billion dollars, the 75th consecutive month of surplus.