Labor regulators find merit in union accusations against Amazon.

In a sign that federal labor officials are closely scrutinizing management behavior during union campaigns, the National Labor Relations Board informed a lawyer representing workers at Amazon this week that it had found merit in accusations that the company had violated labor law.

The labor board found merit to charges that the company had required workers to attend anti-union meetings at a vast Staten Island warehouse where the Amazon Labor Union won a stunning election victory last month. The determination was communicated to the union Friday by an attorney for the labor board’s regional office in Brooklyn, according to Seth Goldstein, a lawyer representing the union.

Such meetings, often known as “captive audience” meetings, are legal under current labor board precedent. But last month, the board’s general counsel, Jennifer Abruzzo, issued a memo saying that the precedent was at odds with the underlying federal statute, and she indicated that she would seek to challenge it.

In the same filing of charges, the Amazon Labor Union accused the company of threatening to withhold benefits from employees if they voted to unionize, and of inaccurately indicating to employees that they could be fired if the warehouse were to unionize and they failed to pay union dues. The labor board also found merit to these accusations, according to an email from the attorney at the regional office, Matt Jackson.

Mr. Jackson said the agency would soon issue a complaint reflecting those accusations unless Amazon settled the case. The complaint would be litigated before an administrative law judge, whose decision could be appealed to the labor board in Washington.

Mr. Goldstein applauded Ms. Abruzzo and the regional office for taking “decisive steps ending required captive audience meetings” and said the right to unionize “will be protected by ending Amazon’s inherently coercive work practices.”

A spokeswoman for the board confirmed the findings. Kelly Nantel, an Amazon spokeswoman, said in a statement that “these allegations are false and we look forward to showing that through the process.”