While some districts will get more aid than they did this year, the letter states, almost all will get less funding than they are entitled to under that state formula.
"Statewide, school districts would lose $750.4 million, bringing the total level of underfunding since 2010 to $3.6 billion," the groups contend.
"Gov. Christie is trying to use budget language to effectively dismantle the framework for school aid established by the Legislature in 2008 and approved by the New Jersey Supreme Court," said Sharon Krengel, policy and outreach coordinator for the Education Law Center, one of the groups that sent the letter to the legislators.
While the state's poorest districts would see the biggest aid cuts, more than 200 urban and suburban districts would not get the minimum amount of aid they are entitled to under the funding formula, she said.
The groups' letter also urges the legislators to increase funding for the state's schools and raise revenue through means such as increasing taxes on high earners.
Barbara Morgan, a state Education Department spokeswoman, defended the state education aid allocation as generous and said the alterations to the funding formula were "commonsense changes" that will "make aid fairer, less susceptible to fraud and abuse, and help to ensure that funding more closely follows each student."
Contact Rita Giordano at 856-779-3841, firstname.lastname@example.org, or on Twitter @ritagiordano.