The research unit expected that exports in the remaining 7 months of the year would expand only 4.6 per cent.
The economic condition of major trade partners - mainly European Union and China - weakened in the second quarter and is unlikely to recover in the latter half.
Thailand's export value in May contracted 5.2 per cent, pressuring the five-month growth figure to only 1.56 per cent, according to Commerce Ministry's data.