(Reuters) -The Strategic Organizing Center (SOC), a coalition of North American labor unions, said on Tuesday it had nominated three candidates for board seats at Starbucks Corp, deploying a tactic typically used by activist shareholders.

Those nominated for election to Starbucks' board are Maria Echaveste, Joshua Gotbaum and Wilma Liebman, who worked in the administrations of former U.S. Presidents Bill Clinton and Barack Obama, the union said in a statement.

The annual meeting, when Starbucks shareholders will vote on the composition of its eight-member board, is scheduled for March 13, 2024.

"The board's nominating and corporate governance committee will review SOC Investment Group's proposed director nominee(s) in accordance with its normal process," Starbucks said in a statement.

It added it had invested more than $3 billion over the last three years on wage increases, training, new equipment and technology, and that it would do so at this pace in 2024. It also said it had increased hourly pay by nearly 50% since 2020, offered more working hours and recorded lower staff turnover.

Workers at several Starbucks stores walked off their jobs last week in a strike organized by the Workers United union during a key promotional event demanding improved staffing and schedules.

SOC said the National Labor Relations Board, a federal agency that upholds workers' rights, has issued more than 120 complaints against Starbucks in the last two years. These include accusations of illegal discipline and firings, store closures to halt union activity, worker surveillance and the failure to bargain with workers in good faith.

"At a time when Starbucks has set an ambitious goal of opening more than 17,000 new stores by 2030, it cannot waste any more resources fighting its own workers," SOC said in a statement.

A National Labor Relations Board spokesperson did not immediately respond to a request for comment.

The union represents more than 9,000 Starbucks employees at about 360 U.S. stores. It is affiliated to Service Employees International Union, which is part of SOC, a shareholder at Starbucks.

Starbucks employed about 228,000 people in the U.S. with 3.6% of Starbucks partners in U.S. company-operated stores represented by unions as of Oct. 1, according to regulatory filing.

Strikes have taken place across industries as a tight U.S. labor market, the expiry of union contracts along with still-high living costs have led to tough negotiations for pay hikes and benefits.

According to preliminary data from the U.S. Bureau of Labor Statistics, nearly 444,900 workers have been involved in work stoppages and strikes through October this year.

Starbucks said on Monday it had created a new board committee dedicated to helping it better engage with stakeholders, including the company's employees.

(Reporting by Ananya Mariam Rajesh and Nilutpal Timsina in Bengaluru and Svea Herbst-Bayliss in New York; Editing by Arun Koyyur and Sherry Jacob-Phillips)