The state is seeking an 85-cent increase to the price of a school lunch under a plan that would bring the cost for a high school student to $3.35, more than double what students paid in 2006.

The price increase, which is expected to take effect next school year, would push the cost of school lunches in the islands to well above the national average of $2.20 and, advocates say, likely spurring many families to opt out of the school meal program and instead pack a lunch from home.

In a memo that included an outline of the changes, the Department of Education acknowledged Tuesday that some families "may not be able to afford this price increase, resulting in more children going hungry."

DOE officials said the proposed price increase — which, if approved, would be the fourth since 2006 — is needed to make up for a $6 million cut in state funding to school food services next school year.

The Board of Education has indicated it will approve the price increase. Members voted Tuesday in favor of a budget request for next fiscal year that assumes the new prices will be in effect.

Lois Yamauchi, president of Parents for Public Schools, said the lunch prices will have a big effect on families that have several kids in public school.

"For a three-child family, that (proposed lunch price) could be almost $10 a day," Yamauchi said. "It creates a hardship."

Randy Moore, the DOE’s assistant superintendent for facilities and support services, said the $6 million in expected revenue from the price increase assumes that up to 20 percent of students who now buy lunch will stop doing so. "It’s getting to be significant money now," he said.

Under the department’s plan, lunch prices for elementary school students would increase by nearly 40 percent, to $3.10 from $2.25. The $3.35 price for middle and high school students represents a 34 percent increase, compared with the $2.50 they now pay.

The price for breakfast would also go up: Students in elementary school would pay $1.70, up from $1; secondary school students would pay $1.85, up from $1.10, according to the DOE.

Students receiving free or reduced-cost meals — who account for 58 percent of all students who participate in the meal program — will not see a price increase. Schools serve meals to about 100,000 students each day.

The proposed prices for lunch would bring Hawaii well above the national average for school meal prices, according to a recently released survey of school districts conducted by the School Nutrition Association.

In the 2010-11 school year, high schools charged $2.20 on average for lunch, while elementary schools charged $1.93, according to the survey, which did not include information about schools in Hawaii or Rhode Island.

School meal prices in Hawaii have been rising steadily since 2001 — when school lunches cost $1 — amid increasing food costs, worsening budget concerns and a state law that requires the DOE to set prices at no less than half of the cost of preparing the meals.

Parents saw lunch prices go up in September, when the DOE increased the cost of a secondary school lunch by 15 cents, but cut the price of an elementary school lunch by a dime. In 2010, lunch prices for all students rose to $2.20, the first increase since 2006, when school lunch cost $1.25.

Principals say the increases over the years have led to much higher enrollment in the federally funded free and reduced-cost lunch program, and to schools offering more small "lunch loans" to parents.

Heather Wilhelm, Mililani Uka Elementary principal, said the higher prices for meals have also spurred more parents to pack lunch for their kids.

She added more parents appear to be having a tougher time covering the cost of lunches and some are requesting "lunch loans" to tide them over for a few days. "Sometimes, we do have parents falling a little bit behind," she said.

Laura Ahn, principal at Kalihi Uka Elementary, said the proposed increases for lunch will be "tough on schools." Parents, she said, are increasingly borrowing from schools to pay for their children’s meals.

"We already have a hard time collecting balances from parents," she said.

The proposed meal-price increases come as public school parents are also being asked to pay more for other services that were historically low-cost or free, including school bus transportation and A+ afterschool care.

Liz Sager, president of PTSA’s Hawaii chapter, anticipates the higher prices will hit the "gap group" hardest. Those are families earning just above what’s required to qualify their kids for free or reduced-cost lunch.

She added that, given the tough economic picture, it’s more important than ever "that Hawaii’s keiki are receiving their adequate nutrition. For many students, that school lunch program is where they’re going to get it."