Birmingham is to receive just #70 per pupil to pay for ambitious Government plans to extend the school day to 6pm.
Schools will organise activities for every child aged 14 and younger, before and after traditional classroom hours.
But there was concern that they were being told to run extra services without the funding to pay for them.
John Dunford, General Secretary of the Secondary Heads Association, said: "The Government must make sure there are adequate resources."
Coun Les Lawrence, Birmingham's Cabinet Member for Lifelong Learning, said the city would meet the challenge.
Birmingham is to receive just over #10 million between 2005 and 2008, including # 1.4 million which had already been allocated to pilot projects in the city, the Department for Education and Skills announced.
This comes to less than #70 - over three years - for each of the 145,000 eligible youngsters in the city.
It is not known how many parents will choose to take up the new services.
The funding, part of a #680 million national package, was announced by Education Secretary Ruth Kelly yesterday.
The new school hours, which have been dubbed "Kelly hours", will run from 8am to 6pm.
They are designed to provide childcare services for every parent who wants it, and increase the number of extra-curricular activities available for youngsters.
The Government yesterday ordered every secondary school to open from 8am to 6pm, by 2010.
Primary schools will also have to offer services for the extended period, but they will be free to provide these on a different site, such as a neighbouring school or private childminding service.
This means some children will face journeys between childcare and lessons.
The West Midlands as a whole will receive #52.8 million over three years, including #10.1 already allocated to existing schemes.
Children will be offered homework clubs, sport clubs, music tuition, visits to museums and galleries, foreign language courses and opportunities to take part in voluntary activities.
Mrs Kelly said: "Schools are at the heart of our communities and it makes sense to extend the services they offer beyond the traditional school day."
She added: "Extended schools will not only help children in their education, but also support hard working families to manage their home and work life."
There would be more funding in future years, Ministers said.
Birmingham city council said it was encouraging headteachers to work together and ensure at least one school offers the hours in every neighbourhood.
Coun Lawrence ( Con Northfield) said: "In Birmingham many schools already provide before and after school provision with breakfast clubs, sports and arts activities, and study support.
"We are also working towards every school in the city over the next five to eight years being part of an extended schools cluster with access to services for children, young people and families.
"Extended schools will make a major contribution to raising performance and, in many areas of the city, break the cycle of deprivation and poverty through education."