Milgram, in a letter to Corzine's chief counsel, said the plan meets constitutional requirements that all New Jersey school children receive a "thorough and efficient" education.
But Newark Mayor Cory Booker, Jersey City Mayor Jerramiah Healy and black legislators - all Democrats like Corzine - worried the plan could lead to deep program cuts and increased property taxes in struggling city school districts.
"We're getting burned by this," Healy said.
The opposition called into question whether Corzine and Democratic leaders could get the plan approved before the legislative session ends on Tuesday.
"I think it will be close, but I think in the end the governor will prevail," said Senate President Richard J. Codey, D-Essex.
Still, Codey acknowledged it would require a lot of lobbying to get the 21 votes needed to pass the bill in the Senate.
The Senate budget panel barely approved the plan Thursday, with the Assembly budget committee holding a hearing that stretched from Thursday afternoon and into the night. Approvals by both panels would set the measure for Monday votes by the full houses.
Booker said he feared the plan was being rushed and that it could bring school cuts and increased property taxes.
"That could have shock waves throughout our city," Booker said.
The plan is designed to send more state aid to suburban and rural schools with growing enrollments and many low-income students.
"It's fair and equitable and predictable," said Sen. Barbara Buono, D-Middlesex, who sponsors the plan.
State Education Commissioner Lucille Davy said the plan "follows the basic principle that children with greater needs deserve greater resources."
But Healy described the plan as "taking from the poor to help the poor."
Under the plan, the 31 poverty-stricken districts that have received extra financial help under a state Supreme Court ruling wouldn't see the same hefty aid increases they've typically received, but other districts - like North Brunswick and Pennsauken - would get 20 percent more from the state next school year.
Every district would get a state aid increase of at least 2 percent next year, and no school would see its allocation decrease for three years.
The plan comes after most school districts saw scant state aid increases this decade, forcing them to rely more on property taxes that are America's highest at $6,330 per homeowner, twice the national average.
Corzine has said the plan "gives all of our children in all of our communities the opportunity to succeed."
"It is balanced, unified and equitable and it provides significant relief to local property taxpayers," Corzine said.
But some Republicans also said Democrats were rushing the plan without proper review and questioned whether it would help the rural and suburban districts. Black Democrats did the same on Thursday.
Sen. Sandra Bolden Cunningham, D-Hudson, said the plan could cost Jersey City schools $110 million over three years, while Sen. Shirley Turner, questioned whether it would boost what are already the nation's highest property taxes.
"I'm just dismayed that we seem to be rushing this through with so many unanswered questions," Turner said.
Yet as urban Democrats expressed worry, suburban Republicans backed it.
Assemblyman Joe Malone, R-Burlington, said he "wasn't totally sold on everything in the bill," but added, "I think the bill is fairer to the state of New Jersey."
Sen. Bob Smith, D-Middlesex, said the plan would eliminate inequities between school districts.
"This is a defendable formula based on the needs of kids," Smith said.
