Unionized workers of Samsung Electronics said Wednesday that they would go on strike next week after failed wage talks with the management -- the first-ever strike in the tech giant’s five decades of history.

"We can’t stand persecution against labor unions anymore. We declare a strike due to the management's attitude of disregarding the workers," the Nationwide Samsung Electronics Union, the largest among Samsung's multiple unions, said in a press briefing held in front of its Seocho office in southern Seoul earlier in the day.

They held a banner that read, “We can no longer tolerate labor repression, union repression.”

The union, which has about 28,000 members, accounting for nearly 22 percent of the company's total workforce, said it would stop work for one day on June 7 as part of broader protest measures.

All company sites across Korea will be affected by the strike, the union said.

If the union members collectively walk out next week, it will mark the first-ever strike by Samsung Electronics workers.

Additionally, an overnight sit-in protest in a bus is planned in front of the Seocho office building starting Wednesday.

“It might be seen as a passive strike, but we will take it step by step. ... It may lead to a general strike, or the strike could fail, but the first strike action itself is meaningful,” the union said.

The union secured the right to strike through the National Labor Relations Commission's decision to suspend mediation and a vote by union members.

The union claimed that the management had no will to continue negotiations in their wage talks that started in January.

The union has demanded a 6.5 percent pay rise and a bonus pegged to the company’s earnings. Unable to reach an agreement with the union, the management set this year's average salary increase rate at 5.1 percent through the labor-management council and paid that to employees last month.

According to industry sources, the unionists held an eighth round of negotiation over wages and collective bargaining agreements a day earlier with the tech giant’s management at the company’s Giheung plant.

Despite previous efforts during practical wage negotiations last week, the current negotiations have stalled due to disagreements over the participation of two company negotiators.

The union requested the exclusion of the two company negotiators but the management refused, resulting in a breakdown of negotiations. As of now, neither side has set a future negotiation schedule.

The unionist defended the decision to take industrial action at a time when some parts of Samsung's business were underperforming.

"The company has been saying they are facing crisis all along for the past decade," a union official said, adding that the firm should not use it as an excuse not to meet its demands.

Last year, Samsung recorded a deficit of 14.88 trillion won ($10.91 billion) in the chip business due to a slump in the semiconductor industry.

Samsung last week replaced the head of its semiconductor unit, saying a new person was needed at the top to navigate what it called a "crisis" affecting the chip industry.

Meanwhile, as the breakdown in negotiations between Samsung Electronics' labor and management continues, Samsung Group United Union, which encompasses the labor unions of five Samsung affiliates, has expressed its position criticizing the NSEU, and an atmosphere of spreading inter-labor conflict can be sensed.

Regarding the NSEU's strike plan, however, the integrated union showed its support for the first attempt to take the walk-off-the-job action at the tech giant. "We hope that collective action can be successful by sufficiently gathering and reflecting the opinions of employees and union members," the integrated union's statement read.

Samsung shares closed at 75,200 won, down 3.09 percent from the previous trading session. The benchmark Kospi was down 1.67 percent.