SANTA FE, N.M. (AP) — New Mexico is threatening to cut off funding at public schools that try to switch to a four-day week as the practice has spread to more than four in 10 school districts across the state.

State lawmakers this month placed a moratorium on additional four-day school scheduling within a general fund spending bill that has yet to be signed by the governor.

Education officials and legislators say it's not clear that student academics and working families are helped by fewer, longer school days, even as teachers and administrators embrace compressed schedules.

School administrators in far-flung districts have pushed back, noting that four-day weeks have become a tool for attracting teachers who can improve academic results at schools with limited financial resources.

"They shouldn't be telling us how to structure our day," said Ron Hendrix, superintendent of Socorro Consolidated Schools, a cluster of six public schools with 1,500 students in central New Mexico. Socorro school board members are scheduled to vote Monday on switching to a four-day week.

"I know how to get student achievement, just let me loose," said Hendrix, who said he previously improved student test scores while moving to a four-day week at another New Mexico school district.

New Mexico sets annual requirements for academic instruction by the hour — 990 hours for elementary school and more for upper grades. Schools can adopt shorter calendar years with longer days and still meet the hourly requirement.

An increasing number of states have moved toward hourly minimum requirements that can lead to four-day weeks, according to Jennifer Thomsen, of the Education Commission of the States that provides research to state policymakers. The commission says 36 states measure the minimum school year in hours, though some also require minimum days as well.

New Mexico lawmakers including Democratic state Sen. Howie Morales of Silver City have said they fear the four-day week will spread in a domino effect as school districts compete with each other for talent — without regard to statewide academics.

A legislative provision would prevent the approval of budgets at districts and charter schools that move to a four-day week but does not challenge existing programs. New Mexico public schools rely on the state for a majority of their funding.

Republican Gov. Susan Martinez has until March 7 to act on the bill, while her administration has expressed support for the freeze.

"The Public Education Department is most interested in the extent to which this is driving improved student outcomes and the verdict is still out," said Lida Alikhani, a spokeswoman for the Public Education Department, in an email.

Out of the state's 89 school districts, 38 mainly rural districts and 22 charter schools concentrated in larger cities have adopted a four-day schedule to cope with a variety of budgetary, training and classroom needs.

Those schools account for about 5 percent of the state's 330,000 public school students.

Jeannie Oakes, a New Mexico-based researcher affiliated with the University of California Los Angeles, said not enough is known to say firmly whether or not four-day schedules hinder or help overall school academics.

At the same time, three-day weekends may have an outsized effect on students from low-income, working families, she said.

"I think people have an image that these kids are in rural areas, that they're going to work on the farm with mom and dad," she said. "But it's not clear if they're spending a day in front of the TV."

Sen. Mimi Stewart, chairwoman of the Legislature's lead education policy committee, said a moratorium buys time for state analysts to study academic consequences.

She said the four-day week is partly a symptom of austere state spending on education in recent years, as districts look for ways to avoid utilities and transportation costs. At the same time, schools are clamoring for state money to expand preschool and extend the school year for students in kindergarten through third grade.

"I don't think (four days) is the best for working families," she said. "I don't think it's the best for students."

Zuni Public School Superintendent Daniel Benavides said the moratorium is a setback for his negotiations with union officials to come up with a more productive schedule. The district has about 1,300 students.

Benavides said his four-day week proposal was geared toward Friday morning professional development sessions for teachers and remedial studies for struggling students — while getting rid of mid-week early dismissals. Native American religious and cultural obligations result in absenteeism on several Fridays each year. About 98 percent of the students are Native American.

Attracting qualified teachers was another goal.

"They're more likely to come because they see that the professional development is built into the week," he said. "But it's mostly to meet the needs of our students."