Eligible families urged to take up free school meals
Cambridgeshire has missed out on about £1m in government funding because 2,500 eligible children have not signed up for free school meals.
The government gives the council a £430 pupil premium for every child registered for the free lunches, and this will go up to £600 next year.
Cambridgeshire County Council said schools would miss out even more if eligible children were not registered.
It wants parents to register even if their children do not eat the meals.
Most families in receipt of income support benefits are eligible.
But they need to sign up by 19 January for the council to receive the pupil premium.
Lisa Faulkner, the child poverty co-ordinator for the county council, said: "We're not forcing children to have school dinners, but we would encourage parents to please register anyway.
"The school will then get the additional pupil premium which will actually be used to directly support those children in their schools."
The county council is basing its figures on the latest statistics supplied by the Department for Work and Pensions of the number of families claiming for income support benefits in Cambridgeshire.
These were sent out in September 2011, but refer back to 2009.
The council then compares the number of pupils claiming its free school meals with the number from all families in receipt of income support benefits.
Ms Faulkner said the extra government money was needed to help children from the poorest backgrounds, because they were less likely to do well at school.
"Almost three quarters of children in Cambridgeshire who have grown up in poverty leave without five good GCSEs," she said.
Families can find out if their children are entitled to the free dinners on the Cambridgeshire County Council website.