In one of the most serious labor disputes to erupt in the culture world since the coronavirus pandemic halted performances around the globe, the Metropolitan Opera said on Monday that it planned to lock out its stagehands at midnight after the union representing the workers balked at the company’s demands for pay cuts.

The Met, which has been shut by the pandemic since March, says that it needs to cut labor costs significantly if it is to survive until and after it reopens. So the company, which has furloughed most of its work force without pay since April, has offered to begin paying many employees up to $1,500 a week if their unions agree to long-term contracts that include a 30 percent cut in pay. Half of those cuts would be restored once the Met’s box office returns to pre-pandemic levels.

The unions have bristled at the request, saying that their members cannot handle such a long-term financial hit after going many months without pay. After talks with the powerful union that represents the Met’s roughly 300 stagehands, Local One of the International Alliance of Theatrical Stage Employees, failed to yield an agreement this weekend, the Met announced that it planned to lock out the union’s workers.

“I realize it is incredibly painful what we’re asking them to do,” Peter Gelb, the Met’s general manager, said in an interview. “But what we’re trying to do is keep the Met alive, and the only way to achieve that is to reduce our costs.”

Of course the lockout will not have its usual impact during the pandemic, when few Met stagehands are working; only a few dozen stagehands have recently been at the opera house, Mr. Gelb said. But more were set to return later this month to begin constructing the sets for the operas that the Met plans to stage next fall, when it hopes to reopen.

Several other performing arts organizations facing a financial crisis as the pandemic has caused them to cancel many months of performances have negotiated pay cuts with the unions representing their workers, including at the Boston Symphony Orchestra and the New York Philharmonic.

After the Met’s lockout begins at midnight on Tuesday, Mr. Gelb said, the stagehands who are currently working on projects like maintaining stage mechanisms will no longer be able to work. He added that if an agreement is not reached by the spring and summer, when the Met usually ramps up its set construction, many more employees will end up out of work.

James J. Claffey Jr., the president of Local One, said in an interview on Monday that during bargaining negotiations he had suggested a lesser pay cut, but that his offer was rejected. None of the stagehands were willing to take a 30 percent cut, he added.

“To do this during a deadly virus is just ridiculous,” Mr. Claffey said of the lockout. “But that’s their leverage at this point.”

Mr. Gelb said Local One’s proposal was insignificant in terms of addressing the problems the Met faces.

Last month, Mr. Gelb sent a letter to Mr. Claffey saying that if they could not reach an agreement by Dec. 5, the Met “will have no choice other than to lock out Local One employees, utilizing other temporary means to construct the sets.” He added that in 2019, the average cost to the Met of a full-time stagehand, including benefits, was $260,000, and wrote that “the health crisis has compounded the Met’s previous financial fragility, threatening our very existence.”

Mr. Gelb has said that most of the pay cuts he is seeking could be achieved by changes to work rules. But the major unions that work with the Met have accused its management of taking advantage of the pandemic to push through concessions that the company has long sought to alter those rules, which have been established over many years of collective bargaining.

Local One’s contract with the Met expired at the end of July. Since Mr. Gelb sent the letter to Mr. Claffey in November, there have been two virtual negotiating meetings, but the deadline Mr. Gelb mentioned passed over the weekend without an agreement.

The Met has asked other unions whose contracts have not yet expired, like those that represent its orchestra musicians and chorus, to open negotiations early and agree to the cuts. In exchange, many of their members would be able to begin receiving partial paychecks for the first time in months. So far, those unions have not agreed to reopen their contracts early.

Adam Krauthamer, the president of the union that represents the orchestra, Local 802 of the American Federation of Musicians, said that his union had made its own proposal for cutbacks that do not “gut their contract for decades to come.” In a statement, he denounced the stagehand lockout, saying that the Met’s revival “should not be at the expense of the very workers who quite literally make the organization function behind the scenes.”

Mr. Gelb contends that reductions in the company’s expenses should not be sought through the pruning of its live presentations. He said that two-thirds of the Met’s annual spending — $200 million — goes to labor costs. The Met’s non-unionized staff has already made sacrifices, he added, including salary cuts, his own foregoing of a salary since the end of March and pre-pandemic cuts to health and pension benefits.

“We shouldn’t be reducing them by reducing our artistic productivity,” he said of the company’s expenses. “Because that is the key to keeping donors on board and getting audiences to come back.”

Mr. Claffey said that the stagehands recognize that the Met has high artistic standards, but added that he rejected the idea that the cost reductions should fall primarily on labor.

“The Met wants labor to assume the entire burden,” he said. “It’s a recipe for disaster.”