A union representing tens of thousands of workers at Samsung Electronics in South Korea said Wednesday it would extend a three-day strike indefinitely in a bid to force management to negotiate.
"(We) declare a second indefinite general strike from July 10, after learning that the management has no willingness to talk," the National Samsung Electronics Union said in a statement.
More than 5,000 members stopped working Monday for what was meant to be a three-day strike, part of a long-running battle over pay and benefits.
The move follows a one-day walkout in June, the first such collective action at the company, which went decades without unionisation.
The union has more than 30,000 members -- more than a fifth of the company's total workforce.
Samsung said Tuesday that there had been no disruption to production, the Yonhap news agency reported, although the union claimed that the strike was having a major impact.
"We have confirmed the clear disruption in production, and the management will regret this choice," the union said in the statement announcing the indefinite strike.
"The longer the strike lasts, the more the management will suffer, and eventually, they will kneel and come to the negotiation table. We are confident of victory."
The union blamed Samsung management for "obstructing" the strike, saying they did not appear willing to engage in dialogue.
It urged more workers to participate, including "those who are still hesitant".
"Your determination is needed to advance our goals and victory. Let us unite our strength to protect our rights and create a better future."
Samsung said it would provide comment later.
The union has been locked in negotiations with management since January, but the two sides have failed to narrow differences.
Workers have rejected the offer of a 5.1 percent pay hike, with the union having previously outlined demands including improvements to annual leave and transparent performance-based bonuses.
Samsung Electronics managed to avoid having its employees unionise for almost 50 years -- sometimes adopting ferocious tactics, according to critics -- while rising to become the world's largest smartphone and semiconductor manufacturer.
Company founder Lee Byung-chul, who died in 1987, was adamantly opposed to unions, saying he would never allow them "until I have dirt over my eyes".
The first labour union at Samsung Electronics was formed in the late 2010s.
The firm is the flagship subsidiary of South Korean giant Samsung Group, by far the largest of the family-controlled conglomerates that dominate business in Asia's fourth-largest economy.
It is the world's largest memory chip maker and accounts for a significant chunk of global output of the high-end chips.
Samsung recently predicted a more than 15-fold increase in its on-year second-quarter operating profits, thanks to growing demand for generative AI.
