HARTFORD, Conn. — A new proposal to expand Connecticut's charter schools could cost some of the state's most impoverished cities more than $1 million annually, a potential source of friction as lawmakers prepare to tackle education reform ideas in their upcoming legislative session.

The proposal would require local districts to pay $1,000 per child for each of their students who attend charter schools. It is one item among dozens in two larger reform packages that Gov. Dannel P. Malloy introduced Monday to expand school choice and overhaul low-performing schools.

That item quickly caught the attention of some local school and municipal officials, who called it unworkable as they struggle to keep class sizes down and avoid layoffs.

Malloy left open the possibility that other funding plans might offset the costs, though, and said "things will become clear" as he rolls out more details on education reform plans when the General Assembly convenes Wednesday.

An analysis of state Department of Education charter enrollment figures obtained Monday by The Associated Press shows that if the $1,000-per-student subsidy is enacted without anything to offset it, New Haven would have to pay more than $1.7 million a year and Bridgeport would be responsible for $1.5 million yearly.

Hartford's bill would be about $1 million. For medium-sized, blue-collar municipalities like Manchester and Norwich, the bill would exceed a quarter of a million dollars per year.

"We do have a major concern about it. What it would do is honor the choice made by parents who put their children in charter schools, at the expense of those whose children remain in the traditional local schools," said Joseph Cirasuolo, executive director of the Connecticut Association of Public School Superintendents.

Nearly 6,100 students attend Connecticut's 17 charter schools. Each of their home town school districts still gets state reimbursement for them — unlike in most states, the money does not follow the child to the charter school — and the state also sends $9,400 for each child to the charter school they attend.

But Cirasuolo and others say the money the districts receive for students who have moved into charter schools isn't separated from other funds or easily segregated to offset the $1,000 that would be charged.

"We don't save $1,000 for every child who leaves their local school for a charter. You'd have to have a whole bunch of children leave from the same grade level and same school, and then you'd have the savings of one teacher (position) — but that isn't the way it happens," he said.

He said the superintendents' group likes many of the governor's other proposals, though, and that he does not believe the potential disagreement on the $1,000-per-child subsidy would overshadow that.

Nor did Hartford Mayor Pedro Segarra, who said he would consider the $1,000 subsidy an investment in the future of his city and its children, and that Hartford would find a way to absorb that $1 million annual cost.

"Where is the money going to come from if we fail these children and we have to ultimately expend an immeasurable amount of resources trying to correct the things we could have avoided?" he said.

Malloy and officials in his administration have worked closely with local school officials and education groups for input on the education reform proposals, but the $1,000 subsidy proposal caught many of them by surprise — a rare moment of discord in what's otherwise been praised by both sides as a collaborative process.

Malloy and lawmakers have said school funding, teacher evaluation procedures, job readiness and many other aspects of education reform will all be on the table when lawmakers convene their session.

"Transforming our educational system — fixing the schools that are falling short and learning from the ones that are graduating high achievers — will help us develop the skilled workforce that will strengthen our state and our economy," Malloy said.

His proposals include allocating $25 million in state funds to overhaul up to 25 chronically low-performing schools statewide over the next two years. The changes could include longer school days, extra pay for skilled teachers who commit to struggling schools and myriad other ideas depending on the overhaul plans for each school.

Malloy also proposes allocating $5.5 million to boost alternative schools such as charter, magnet and community schools; and adopting legislation limiting any new charter schools to high-need districts.

One portion of his proposals that received high praise from teachers' unions would require those new charter schools to prove they are including children with special needs such as learning disabilities and limited English proficiency.

Associated Press reporter Stephen Singer contributed to this story.