Mayor de Blasio's free school lunch plan is under fire from some Jewish groups who say the program's lack of certified kosher meals amounts to discrimination against 30,000 students in yeshivas across the city.

"The mayor is openly discriminating against students in nonpublic and religious schools," Allen Fagin, CEO of the Orthodox Union, told the Daily News. "He is failing children in classrooms across his city."

Unveiled at the start of this school year, the "Free School Lunch For All" program guarantees meals to all of the city's 1.1 million public school students. Private schools are welcome to participate as well, and 115 already do, according to the Education Department.

"We welcome all non-public schools interested in participating in our program and nonpublic schools also have the option of participating in federal meals reimbursement programs independently and directly," Education Department spokeswoman Toya Holness said in a statement.

"The DOE also offers daily alternative options to ensure all students have access to a nutritious meal," she added. Those daily alternatives include vegetarian meals, but none that are certified by a religious authority.

"The mayor rolled out a program where every student in every school—non-public, charter, whatever—is supposed to be eligible," Jake Adler, New York State Policy Director at Orthodox Union, told Gothamist. "Here you have a program where they're not eligible, so that's not a universal program."

"Over the next few weeks we'll be rolling out a broader coalition—it's not just a Jewish issue but certainly also a Muslim issue," Adler added.

According to Public Advocate Letitia James, Jewish and Muslim students make up 38 percent of the public school population.

Earlier versions of the bill included a provision mandating that kosher and halal food options be made available in schools where more than a quarter of students requested them. That requirement was cut from the final law.