The union representing N.B.A. players is accusing the league of engaging in unfair labor practices and has filed a charge with the National Labor Relations Board.

In the complaint, which was announced Tuesday afternoon, the National Basketball Players Association accuses N.B.A. officials of “failing to bargain in good faith” on a new collective bargaining agreement. Other “unlawful practices” cited by the union include “demanding huge financial takeaways” without offering “corresponding concessions” to the players; “bypassing the union to deal directly with players”; and “threatening an unlawful lockout.”

The union is seeking an injunction to stop “the N.B.A.’s unlawful bargaining practices and its unlawful lockout threat.”