Unionised workers at South Korea's Hyundai Heavy Industries (HHI) have voted to strike over wages.

The ballot on Wednesday reflected the lack of progress in pay negotiations, the Yonhap news agency reported.

The labour union said nearly 60% of members voted to walk out for three hours on Thursday.

They want a rise in basic pay of $104, plus higher performance-based rewards.

Workers have already staged protests this year after HHI bought rival DMSE.