The Metropolitan Opera is seeking concessions from its unions, whose contracts are up at the end of July, as it begins a round of labor negotiations that promise to be contentious.

Peter Gelb, the Metís general manager, met this week with officials of Local 802 of the American Federation of Musicians, which represents the players in the orchestra, and proposed curbing the opera houseís costs by reducing pension and health care benefits and changing work rules, according to three people with knowledge of the proposal who requested anonymity because they were not authorized to speak publicly.