New figures from the Central Statistics Office show that seasonally adjusted goods exports fell by 4% to a total of €8.259 billion in September compared to August.
The CSO said that seasonally adjusted imports eased by 3% to €4.921 billion which resulted in a seasonally adjusted trade surplus of €3.338 billion September, down 7% from the August figure.
This September surplus was the second lowest so far in 2015 after March's figure of €3.220 billion and reflected a general weakening in global trade, analyst said.
Today's figures show that exports of medical and pharmaceutical products rose by 14% to €2.314m in September compared to the same time last year.
Exports of essential oils increased by 17% to €616m and exports of electrical machinery, appliances and parts jumped by 24% to €250m.
The CSO said the EU accounted for 58% of total goods exports in September, while the US was the main non-EU destination as it accounted for 22% of total exports during the month.
Meanwhile, imports of petroleum plunged by 47% in September, while imports of other transport equipment, including planes, dived 82%. Imports of organic chemicals, however, jumped by 86%.
The EU also accounted for 60% of the value of goods imports in September, with 28% of total imports coming from the UK. The US (14%) and China (9%) were the main non-EU sources of imports.
Commenting on today's figures, Merrion economist Alan McQuaid said that the country's trade balance has fallen for the past four years, but this year it should increase for the first time since 2010.
"Based on the latest trade figures from the CSO the surplus for last year as a whole is put at €31.778 billion The overall surplus in 2015 is in our view now likely to be in and around €41 billion," he added.