Two of opera’s biggest stars have left the Met in the lurch for Tokyo performances.

The New York Metropolitan Opera’s most celebrated singers have pulled out of a major tour to Japan, citing concerns about radiation leaks caused by the March 11 earthquake.

Russian-born soprano Anna Netrebko and Maltese tenor Joseph Calleja withdrew from their scheduled Tokyo and Nagoya appearances in  La bohème, Don Carloand Lucia di Lammermoor,which open on Saturday and run until June 19. About 350 cast and crew members arrived in Japan on Monday for these performances.

Netrebko has garnered international acclaim in the title role of Donizetti’s Lucia di Lammermoor,which was beamed to cinemas around the world as part of the Met’s Live in HD series.

The late cancellations “forced the Met to scramble over the weekend to find replacement stars,” the company announced in a statement.

The 39-year-old Netrebeko said the emotional strain of performing in Japan with the nation still in recovery would be too much for her, having lived through the nuclear disaster of Chernobyl.

“She didn’t feel that she would be able to present her best performances and didn’t want to disappoint her Japanese fans. Mr. Calleja also had last-minute misgivings about performing in...