Families struggling with the cost of living may have to wait until after Christmas for financial help.
Household Support Fund payments of £80 per child are available to help families in Cornwall who receive free school meals.
But Cornwall Council said the Post Office had taken "a little longer to create these payments than was originally expected".
The money comes from central government and Cornwall Council said staff were working to ensure families of eligible children get their £80 per child support payment as soon as possible.
"We'd hoped that codes would be sent to schools this week, before the end of term, so they could be redeemed for cash at Post Offices before Christmas,” said the council in a statement.
"Unfortunately it's taken the Post Office a little longer to create these payments than was originally expected so schools may not have enough time to issue all codes before the end of term."
Anyone seeking help can visit www.cornwall.gov.uk/benefits-and-support/cost-of-living-support-for-rising-energy-costs/