The Tories say ministers have mismanaged the rebuilding scheme
Local authorities have spent £170 million on consultants in a government scheme to refurbish and rebuild schools in England, the Conservatives say.
They say the £50 billion Building Schools for the Future programme has delivered "hardly any improvements".
The Schools Secretary Ed Balls defended the scheme and accused the Conservatives of planning to make cuts.
The government says 87 schools have been improved or rebuilt, with a further 33 due to open within days.
But the Shadow Children's Secretary Michael Gove questioned whether it was value for money.
He said that since Building Schools for the Future (BSF) began in 2004 a new school had opened in just 15 local authorities.
He said consultants had been paid by local authorities bidding for the construction work and for giving advice about the work itself. The information was obtained via the Freedom of Information Act.
He said: "In tough economic times it is vital that ministers get good value for taxpayers' money.
"But under the government's bureaucratic school refurbishment scheme, millions has already been spent on consultants with hardly any improvements actually delivered."
Mr Gove predicts that consultants could go on to earn a total of £1.5 billion from the scheme.
He added: "We need a government that is able to get more for less. Ministers have already increased their costing by £10bn due to their failure to deliver the scheme on time.
"At a time when family budgets are more stretched than ever, we simply cannot afford this level of mismanagement in Ed Balls's department."
Mr Balls hit back, accusing the Tories of planning to save money by allowing new schools to open in office blocks.
He said: "Thanks to this government's sustained investment in new school buildings, leaking roofs and freezing classrooms are now simply for the history books.
"As we will show this week, we are ensuring that children have places to learn which are fit for the 21st century with state of the art classrooms, sport and music facilities - not consigning them to an office block as the Tories seem happy to do."
The government agency responsible for the building programme, Partnership for Schools, said spending on consultants was widely in line with its recommendations.
A spokesman said: "We give an indicative steer that councils should expect to spend around 3% of the total value of their BSF scheme to ensure successful delivery locally.
"Some local authorities spend more than this amount whilst others spend considerably less.
"As recent independent industry research demonstrates, the average amount that local authorities spend is 3.2% of the value of their overall project.
"We expect these costs to come down further over time as local authorities and the private sector build on their experience and knowledge to date."
Tim Byles, Chief Executive of Partnerships for School, the government agency responsible for the programme, said almost 110,000 pupils in 120 schools in 32 local authority areas were benefitting from the difference that BSF investment is making to their education and to their futures.
He said: "BSF is not just about providing new buildings. It is about providing safe, welcoming and inspirational spaces and resources where all learners are encouraged to reach their full potential."