Hyundai Heavy Industries (HHI) has been hit by a strike on Thursday after wage talks failed.
The Yonhap news agency said the first full walk-out in 23 years started at 0800 local time.
Partial strikes were carried out in 2015 and 2016.
Only about 10% or 1,500 staff took part, the labour union said.
HHI said the action did not cause any serious missed output, with workers from smaller contractors making up nearly 70% of its workforce.
It
