MADISON, Wis. — Thousands of students will apply by the deadline to receive taxpayer-funded vouchers to attend private and religious schools, far exceeding the 500 cap on enrollees, a leader in the movement to grow the program predicted Thursday.

If more than 500 students apply by Friday, as School Choice Wisconsin president Jim Bender said was expected, only the 25 schools with the most applicants will be allowed into the newly expanded program. Forty-eight private and religious schools applied last month to participate.

Bender said he had estimates from 20 of the schools that about 1,600 students intended to apply. That includes a mixture of students in public school and those already attending private school, he said.

The voucher program, which provides a taxpayer subsidy to pay for a private school education, currently operates only in Milwaukee and the Racine area. But Gov. Scott Walker and the Republican-controlled Legislature expanded the program across Wisconsin in the state budget passed last month, at a cost of about $10.5 million.

Supporters argue the voucher program gives parents whose children are in underperforming schools an alternative, while opponents say the private schools are unaccountable, take valuable resources away from public schools and are part of a broader agenda to defund public education.

Only families earning up to 185 percent of the federal poverty level, or $43,752 for a family of four, are eligible in the new schools. Married couples with two or more children can earn up to $50,752 and still qualify.

The deadline to apply is 4 p.m. Friday. The state Department of Public Instruction plans to release details about how many students applied, and which schools will be in the program, late next week.

After severe storms knocked out power at the St. Francis Xavier Catholic School System in Appleton on Tuesday night, school officials worked to directly contact families that had expressed interest and set up shop at another location that had electricity to process applications.

Ray DuBois, president of the school system that has about 1,600 students in kindergarten through 12th grade, said he expected about 200 families to apply for vouchers, including both new and existing students.

"In spite of what's happening power-wise and Internet-wise and phone-wise, a lot of people pulled together very quickly to get us in a good position," he said.

Individual schools, as well as a coalition of groups that favor vouchers, mounted a massive campaign to generate applications during the eight-day window that began Aug. 1. That effort included mailing 55,000 post cards and placing 40,000 automated telephone calls to targeted parts of the state, including Green Bay, Sheboygan and Beloit, said Brian Pleva, a lobbyist for the American Federation for Children.

Pleva said he couldn't estimate how many applicants there would be, but "I'm sure it will be over 500 ... Unfortunately there will be parents who won't be able to get their child in the program this year because of the enrollment cap."

Setting the enrollment cap at 500 this coming year, and 1,000 after that, was one of several parts of the voucher expansion plan that were negotiated by the Legislature, Walker and advocates.

If more than 500 students apply, each of the 25 schools with the most applicants will be guaranteed 10 spots each. The remaining 250 will be randomly assigned. That will give the schools with more applicants better odds of getting the slots than those with fewer.

The voucher program has a long history in Wisconsin. It began in Milwaukee in 1989 and was the first of its kind in the country. In 2011, the program expanded to Racine and income eligibility levels for those two cities were increased to 300 percent of the federal poverty rate.

That income eligibility is more liberal than in the expanded districts, which are also under the enrollment cap.

There is no limit on enrollment in the Milwaukee program, which gave out 24,000 vouchers this school year. Racine reached its cap of 500 vouchers this year, but there will be no limit starting next year.