By Julia Love

SAN FRANCISCO A regional director for the U.S. National Labor Relations Board on Friday ordered a union election for a group of workers at an Activision Blizzard-owned studio that works on the popular "Call of Duty" franchise, overruling objections from the company.

In a 27-page decision, Jennifer Hadsall, a regional director in Minneapolis, ordered ballots to be mailed to employees on April 29. Workers will have until May 20 to return their ballots, and counting will begin on May 23, per the decision.

The election will cover roughly 21 workers in the quality assurance department at Raven Software in Middleton, Wisconsin. The workers will vote on whether to join the Communications Workers of America, a union that has played an active role in organizing tech employees in recent months.

The vote also comes amid a surge in labor activity by workers in the tech sector. Employees at an Amazon warehouse in Staten Island, New York recently voted to unionize and workers at an Apple store in Atlanta filed a petition for a union election.

An Activision Blizzard spokesperson said the company was "reviewing legal options regarding a potential appeal."

"We are disappointed that a decision that could significantly impact the future of our entire studio will be made by fewer than 10% of our employees," the spokesperson said in a statement. "We believe a direct relationship with team members is the best path to achieving individual and company goals."

Activision had urged the NLRB to dismiss the petition for a union election, citing a recent reorganization, and argued that any vote on unionization should be conducted among a much larger group of employees. But Hadsall ruled that the proposed unit should stand, finding that the QA testers that the union seeks to represent have a "meaningfully distinct collective-bargaining interest."

In recent months, Activision Blizzard workers have banded together to try to influence the company's future, including staging a walkout and circulating a petition calling for the removal of Chief Executive Officer Bobby Kotick. Microsoft announced plans to acquire Activision in January.

The NLRB decision was previously reported by Bloomberg.

(Reporting by Julia Love; Editing by Bernard Orr)