A month after SUNY revealed a plan to let charter schools certify their own teachers, a top official in charge of finalizing it says changes could soon be in the works.

Joseph Belluck, the head of SUNY’s charter school committee, said he has found some of the critiques lodged against the plan convincing.

At the top of the list, he said, is the possibility that the proposal would essentially trap teachers in their charter schools.

The proposed credential would apply only in SUNY-authorized charter schools, meaning that teachers who wish to move to a city-run school, or even another charter school, might have to seek additional training to do so.

“It’s definitely something I’m concerned about,” said Belluck, who heads the committee that must approve the rules. “I would expect there will be some changes to try to address this issue.”

Those changes could include working with schools to make a smooth transition from a charter school certificate to a full, state-certified credential, he said.

A local nonprofit group, Education Trust-New York, suggested some of those strategies in a letter to SUNY explaining the group’s objections to the plan.

The proposal, the group said, could lead to “two tiers of certification,” in which charter school teachers would be trapped at one set of school. They suggested working with the Board of Regents to create a formal path to full certification.

Other changes that are possible, Belluck said, include identifying a plan to tell whether programs are effectively preparing teachers, something that Ed Trust asked for, and increasing the number of hours of instruction required.

The proposal requires teachers to spend just 30 hours on classroom instruction and 100 hours of practice teaching, far less than teachers must complete now to be certified.

The state teachers union charged that the thin time requirements would “significantly undercut the quality of teaching in charter schools.” New York City’s union is also asking members to oppose the proposal, arguing that charter schools should focus on retaining teachers, not figuring out the fastest way to attract new ones.

Belluck said the time requirements are under review.

“It’s possible that there will be some changes to that in terms of increasing the number of hours, “Belluck said. “We haven’t landed in any particular place yet.”

The proposal could come up for approval as early as late September.