David Cameron has dismissed speculation free school meals for all infant children could face cuts.
The prime minister "is committed to free school meals in England", an official spokesman told the BBC.
The coalition government introduced the meals a year ago for all pupils in the first three years of school in England.
But there has been speculation the meals are at risk, after Chancellor George Osborne demanded cuts of between 25% and 40% from unprotected budgets.
The spokesman said the prime minister had made the point that "it was in the manifesto, the manifesto words are very clear - we're proud of what we've done with free school meals".
The Conservative manifesto says: "We will support families by providing free meals to all infants".
The chancellor called for the cuts in July, as part of his spending review, due to be published in November.
The free school meals budget has cost about £600m each year, and there had been speculation over its future.
But the Department for Education has indicated that free school meals will be protected in the spending review.
"We believe that every child, regardless of their background, should have the same opportunities," said a spokesman.
"That is at the heart of what we are doing with school food.
"No child should be hindered because they are not eating a nutritious meal at lunchtime.
"We have provided significant financial support to schools to help them deliver universal infant free school meals.
"We have come a long way, and the new School Food Standards mean pupils of all ages are eating good food that sows the seeds for healthy eating for life."
At the weekend some 40 top health professionals signed a letter warning that scrapping the meals could harm children's health.
"It would be short-term thinking indeed for the government to cut the funding for universal infant free school meals," said the letter.
The National Association of Head Teachers called for "a swift and unequivocal statement" from government that it would honour its general election pledge to fund a meal for all infant children.
"That message could and should be delivered straight away," said NAHT general secretary, Russell Hobby.
"Schools signing contracts with catering companies this term can't afford to wait until the November spending review only to find out the policy has been changed."