Every city agency has to tighten its belt under Mayor Michael Bloomberg's proposed budget, but when it comes to funding for children's programs, City Council members said the mayor had gone too far.

"This budget is being balanced on the backs of children," said Brooklyn Councilman Lewis Fidler.

That was the theme Thursday at a contentious budget hearing and a protest on the steps of City Hall. Council members were upset by proposed cuts to after-school programs, homeless youth, literacy services and the city's summer jobs programs.

By the council's count, City Hall is preparing to cut overall youth program slots by close to 44 percent, by slashing more than 100,000 seats for children.

"It's not seats and it's not slots. It's kids, it's families," said Manhattan Councilwoman Margaret Chin.

City Youth and Community Development Commissioner Jeanne Mullgrav said funding cuts from Albany and Washington are stretching her department's budget thin.

"The city is really doing the lion's share of the work. And I think that is one of the problems," said the commissioner.

The City Council may have a track record of restoring funding for youth programs that get axed in the mayor's budget, but this year there are a lot of competing priorities.

"In a year like this I don't think we can count on anything," said Michelle Yanche of Good Shepherd Services.

In early May, Bloomberg tried to tamp down some of the anger over his budget plans by restoring $40 million to help save many of the 16,000 child-care spots on the chopping block. Aides to the mayor say every child receiving subsidized care now will be able to get it for another year.

However, that did little to appease critics of the funding plan to help children.

"There are thousands of children that are going to be out on the street and there are communities that are being left out and neglected," said Brooklyn Councilman Domenic Recchia.

City Council members say they will keep fighting to pump additional dollars into these programs. A final budget deal is due by the end of June.