(Reuters) - The U.S. Senate on Wednesday rejected Democratic President Joe Biden's nomination of a U.S. labor board official for a new term, giving President-elect Donald Trump a chance to cement Republican control of the agency soon after taking office.

The Senate voted 50-49 against holding a confirmation vote on the nomination of National Labor Relations Board Chair Lauren McFerran, whose term expires next week. Senators Joe Manchin of West Virginia and Kyrsten Sinema of Arizona, both Democrats who left their party during Biden's term after repeatedly bucking his legislative priorities, provided the decisive votes.

Democrats could make another attempt to hold a vote, but it would likely be futile.

McFerran's nomination was strongly opposed by business groups and many Republicans, who cited a series of recent NLRB decisions and rules that they say unfairly favored unions.

The NLRB generally has three members from the president's party and two from the opposing party. Because their terms are staggered, control of the agency typically does not change hands for a year or two into an administration.

Without McFerran, Democrats will hold a 2-1 majority at the NLRB, which enforces workers' rights to join unions and advocate for better working conditions. That means Trump, who takes office next month, could move quickly to shepherd two nominees through the Senate.

The Senate vote was praised by business groups. McFerran's tenure has been characterized by contentious decisions and legal challenges that have drained NLRB resources and overturned established legal precedents, said Glenn Spencer, vice president of employment policy at the U.S. Chamber of Commerce, the country's largest business lobby.

"The NLRB should be focused on promoting fairness, not tipping the scale in favor of a select few in organized labor at the expense of workers and businesses alike," he said.

The Chamber and other opponents of McFerran's nomination have criticized several recent board rulings, including ones that created a path to unionize outside of the longstanding secret ballot election process and made it more difficult to classify workers as independent contractors who cannot join unions. Trump's appointees to the board are widely expected to reverse those decisions.

The White House and an NLRB spokesperson did not immediately respond to requests for comment.

Biden had also nominated Joshua Ditelberg, a labor lawyer who represents companies, for a Republican seat on the board. Senate Democrats withdrew a motion to hold a vote on Ditelberg after the vote on McFerran.

Along with appointing new members, Trump is expected to fire NLRB General Counsel Jennifer Abruzzo, a Biden appointee who has aggressively pushed a number of legal arguments favored by unions since she was confirmed in 2021.

The general counsel acts like a prosecutor, bringing cases alleging illegal labor practices before administrative judges and then the five-member board, whose decisions can be appealed in federal appeals courts.