Schools in England are being promised an extra £1.3bn per year in their budgets, alongside a shake-up of how funding is allocated.
But the cash for schools will be taken from elsewhere in the education budget, such as building free schools.
Education Secretary Justine Greening said she recognised there had been public concern over school funding during the general election.
But Labour’s Angela Rayner said there “wasn’t a penny of new money”.
“They are not committing any new money and have not been clear about exactly what programmes they will be cutting to plug the funding back hole,” said Ms Rayner.
Ms Greening told the House of Commons said that this “significant investment” would help to “raise standards, promote social mobility and to give every child the best possible education”.
“The government finally appears to be listening,” said Jules White, a West Sussex head teacher who co-ordinated a campaign over funding shortages.
But he cautioned that any increase would need to keep up with “rising pupil numbers and inflationary costs”.
Geoff Barton, leader of the ASCL head teachers’ union, said this was a “step in the right direction and an acknowledgment of the huge level of concern around the country on this issue”.
But he said schools would still have to see the implications of the money being “saved from elsewhere in education budget”.
Chris Keates leader of the NASUWT teachers’ union called Ms Greening’s statement “a recycled announcement of recycled money”.
School funding became a major issue during the general election, with school leaders and teachers’ unions warning that budget shortages would mean cuts to staffing and subjects.