The manufacturing production index (MPI) declined a bigger-than-expected 14.69% in July from a year earlier, led by lower production of cars and petroleum amid the coronavirus outbreak, the Industry Ministry said on Wednesday.
That compares with a forecast fall of 13.9% in a Reuters poll, and against June's revised contraction of 17.8%.
Capacity utilisation in July was 56.01% after June's revised 55.07%.
The ministry expects the MPI index to fall by 8%-9% this year, it said.
Industrial goods account for 80% of total exports, a key driver of Thai growth, which contracted 11.37% in July from a year earlier.