WASHINGTON — As the economy struggles to regain its footing, more children than ever receive free or reduced-price lunches in the nation's school cafeterias.

And some advocates suspect even more children could use the help.

As of this month, 62 percent of public school students who participate in the National School Lunch Program have shown they cannot afford the average $2.92-a-day price for a hot lunch, according to the U.S. Department of Agriculture's Food Nutrition Service.

More than 31.2 million children receive the benefit.

"It's almost inconceivable to think, when we're walking around with our four-dollar lattes, that there are families who can't afford two dollars a day for a week," said Cathy Schuchart , vice president of child nutrition and policy with the School Nutrition Association, an advocacy group based in Washington.

A USDA study this year found wide disparities among states in signing up children who receive food stamps for the school lunch program. And although most families routinely receive applications before school starts, many don't know that they can sign up midyear if a parent loses a job or faces some other hardship.

"I suspect there is more need than is indicated," said Maureen Furr , principal at South Mecklenburg High School in Charlotte, N.C., where one in three children receives a free or reduced-price lunch. "There's no question in my mind that people are in more difficult circumstances."

To qualify, a family of four must earn $28,665 or less for a free lunch; $40,793 or less to get lunch at a sharply reduced rate.

"Kids shouldn't have to worry about that part of their lives," said Kim Short , principal of Ballentine Elementary School in Fuquay-Varina. "It's certainly a school issue. But it's a community issue, too."

U.S. Rep. Bob Etheridge , a North Carolina Democrat and a former state schools superintendent, worried this fall that the program wasn't reaching everyone who qualified.

In a letter to school principals in his district, Etheridge pointed out that nationally, federal nutrition assistance such as food stamps jumped 22 percent in the past year, while the applications for free and reduced lunches had risen just 3 percent.

"I am writing to encourage you to reach out to your students and their parents," he wrote. "Families who are newly experiencing economic stress may not be aware that they are eligible."

The federal government has worked on bringing more families on board. Under federal law, states were told five years ago to automatically sign up families who receive food stamps for the free and reduced-price lunch program.

This spring, Congress takes up the Child Nutrition Act, which governs all aspects of school lunches. Advocates such as Schuchart want to see national standards for nutrition, but they also are pushing for a higher federal reimbursement rate for school districts. Their long-term goal is to eliminate reduced-price lunches, allowing for all qualifying pupils to receive free meals.

Now, the USDA gives back $2.57 to school districts for each free lunch served. That doesn't cover all the costs, leaving local districts to make up the funding through sales of other, usually less-nutritious foods.

Schuchart's group wants the reimbursement rate raised about 35 cents per meal.

School officials say they often worry about whether children are eating well. A USDA study last month found that 17 million households face "food insecurity," meaning it's tough to put food on the table.

Privately run programs such as "Backpack Buddies" allow especially needy schoolchildren to take home a bag of food over the weekend to sustain their families. School officials worry about needy children at home over the long winter break, and whether their families have enough food.

Interfaith Shuttle, which runs the Backpack Buddies program in seven central North Carolina counties, sent home about 800 family boxes to help kids get through the holidays, said Jason Boone , the agency's spokesman.

In rural Hoke County, where 63 percent of students receive free or reduced-price lunches, Deborah Davis Carpenter , the director of Child Nutrition Services, said several parents have come in this fall with check stubs showing reduced pay, asking to redo their forms.

She remembers last January, when about five families came into her office asking for help.

"One father told me, 'You do not know what you've done to help me. This takes off the pressure, to know that my children can have lunch every day and there's not going to be a bill,' " recalled Carpenter, who is president of the North Carolina School Nutrition Association.

Carpenter said she fears more families will fall onto hard times in the new year.

"I'm nervous about it. I really am," she said. "The children whose parents don't have a lot of money, we're not sure how they eat."