Prince George’s school officials traveled to the Philippines and other countries in 2005, searching for teachers who could meet stricter standards called for in the federal No Child Left Behind Act.

Since then, the school system has amassed more than 1,000 foreign nationals as employees — the vast majority of whom are dependent on special visas allowing them to work in the United States.

Many of those foreign employees are now consulting a lawyer. They contend that the school district, faced with the prospect of cutting about 1,300 positions, is creating an unfair standard for laying off teachers recruited from foreign countries — a group that is largely made up of Filipinos.

The concern grows from new standards released in closed-door meetings this month. Prince George’s will now renew the three-year visas only for teachers who are in designated “critical” areas — such as special education, English as a second language, and high school math and science.

The small number of teachers who specialize in other areas, such as pre-K education or social studies, will not have their visas renewed.

“Where is the fairness?” asked Arnedo S. Valera, an immigration lawyer and executive director of Migrant Heritage Commission. “They came to the Philippines actively recruiting them, and they’ve performed well. Now, you’re dismissing them?”

Valera said his group is reviewing immigration laws to see whether this standard is discriminatory.

Synthia J. Shilling, the school system’s human resources director, said the change affects a limited number of educators. The majority of the foreign educators were recruited to teach in critical areas. Some have gained permanent residency status and no longer need to be sponsored.

The school board has received applications for visa renewal from 83 employees this year, about half of the foreign staff whose sponsorships are about to expire.

Only four of those applications been denied so far, Shilling said.

The school system’s $155 million budget gap had prompted a review of hiring practices, Shilling said. The visa, known as the H1B, is contingent on employers not being able to find citizens who can perform specific jobs.

Some of the positions held by foreign teachers could be reassigned to other teachers at risk of being laid off. Shilling said no one would be asked to leave until their visa expires, the last of which will be in 2014.

“This is a difficult process, and our employees have given wonderful service to our schools,’’ Shilling said. “The budget is absolutely the basis of this decision.’’