Funding of £107m is enough to ensure a "radical" new curriculum will be available for three to seven-year-olds in Wales, says the education minister.
The Foundation Phase will see children learning through play
Jane Hutt was responding to concerns about the Foundation Phase from two teaching unions, the NAHT and NUT.
They warned that plans to roll it out in September would fail unless more money is put into the project.
But Ms Hutt said her department was working with local education officials to ensure the money was in place.
The Foundation Phase has been described as one of the biggest changes in early years learning in a generation.
Instead of the traditional classroom learning, children instead learn through play.
BBC Wales education correspondent Colette Hume said this radical approach was one which many teachers involved in the pilot projects support wholeheartedly.
But she said it would rely for success on a much smaller ratio of children to staff, which will be costly.
An extra £33m was announced for the scheme in January by the Welsh Assembly Government.
But the NAHT (National Association of Head Teachers) and NUT (National Union of Teachers) claimed the proposal remained under-funded, which put plans for a September launch in doubt.
However, Ms Hutt said: "Total additional funding for the Foundation Phase now stands at over £107m.
"This will support the Welsh Assembly Government, local authorities and schools to deliver the Foundation Phase for three to seven-year-olds, which is designed to give children the best possible start and provide opportunities to learn and develop during the early years.
"We are working closely with directors of education and the Welsh Local Government Association to ensure funding is in place appropriately to meet our expectations."