NEW YORK — The city is scrapping a bureaucratic hurdle to get qualified teachers in front of thousands of migrant children, as public schools face a shortage of bilingual educators on the first day of classes.

Teachers with more than one certificate — that can include expertise in bilingual or English as a new language programs — are often dissuaded from switching subjects, due to strict tenure rules that require them to start over accruing seniority.

But the immediate changes announced Thursday will give tenured teachers in other subjects, who also have the skill set to teach the newcomer students English, automatic tenure — freeing up another 500 to 600 educators to pivot without impacting their careers.

“We’re activating a special group of teachers who already work in our schools,” said Banks at P.S. 121 Throop School in the Bronx.

More than 2,500 asylum-seeking children enrolled in the city’s local public schools this summer. That’s on top of the 18,500 migrant students who had arrived by the end of last school year.

“If you’re teaching one subject,” Banks explained, “and you only have tenure in that subject, and yet your school really needs you now to teach ENL or to teach bilingual education, they don’t shift to do that because they don’t want to give up their tenure in their primary license.”

“This is going to ensure that we get more teachers in the classrooms right away who can help them meet this gap,” the chancellor said.

While the number of migrant children in local schools has been swelling for more than a year now, the city has yet to move the needle on hiring enough teachers to serve them.

The public schools are expecting to employ 3,400 teachers licensed to teach English as a new language and 1,700 certified bilingual teachers in Spanish this fall, compared with 3,600 English as a second language teachers and 1,600 Spanish bilingual teachers the year before, according to city and Independent Budget Office data.

More than 360 of those are new hires between the two certificates, with another 260 candidates available who are being processed, education officials said this week. It remains to be seen how many teachers take advantage of the eased tenure restrictions.

The vast majority of students who speak another primary language — more than 8 in 10 — receive language instruction through English as a New Language programs, according to Deputy Chancellor of Teaching and Learning Carolyne Quintana, which offer less instruction in students’ home languages than bilingual education and is considered a less desirable placement.

The city added 33 new bilingual programs last year, and is rolling out another 44 this year in response to the demand, she said.

After years of enrollment declines, Banks has stressed that there is space in the public school system for the newcomer students, but said this week the influx has led to some overcrowded classrooms in School Districts 2 in Manhattan, 9 and 10 in the Bronx, and 24 and 30 in Queens.

It was not immediately clear where the hundreds of existing teachers are currently working and if they are in schools with concentrated need.

“There’s bureaucratic red tape that’s been in effect for decades,” said UFT President Michael Mulgrew, “that does not really meet the needs of the schools. And right now, we need to stop this silliness.”

Teachers who gave up their seniority to switch subjects also put themselves at increased risk of being let go by their schools when budgets are tight or fewer students enroll.

“If we have teachers who are certified as bilingual, ENL teachers, then we need to be able to let them switch their certificates without any liability to themselves,” Mulgrew added. “They’ve already proven to be highly successful teachers. To receive tenure is not an easy thing — it’s our vetting process.”

Alongside a need for more Spanish-speakers, union officials said more bilingual teachers are needed in Urdu, Punjabi, Russian and other languages. More than 200 different languages and dialects are spoken in city public schools.

The change is an emergency measure that will expire after the 2023-24 school year, though Mulgrew said he was hopeful about permanent updates to the state regulation. The policy shift does not currently apply to other school districts throughout the state.

The day before, Gov. Hochul indicated the state could revisit some of its funding and policies.

“We are working to help support the city,” Hochul told reporters at a back-to-school event Wednesday. “We’ve given a record amount of money to education… So the resources are there for hiring.”

“But absolutely, when we go into our budget next year, we’re going to have to take a look at the big picture,” she added. “What else can we do to help support recruitment and more teachers with these languages?”