The National Association of Schoolmasters Union of Women Teachers, at its annual conference in Eastbourne, said the funds, which would pay for 23,000 teachers, were being "squirreled away".
Nigel de Gruchy, the union's general secretary, accused some headteachers of building up reserves to fund their own discretionary pay rises. He said: "The heads have got their noses in the trough. The system is semi- corrupt."
Delegates were told that one London school was holding reserves of pounds 800,000, while others were profiteering by replacing experienced teachers with cheap, newly qualified staff.
Delegates backed a called for fundamental reform of the school funding system and called on the Government to launch an inquiry.
But John Dunford, general secretary of the Secondary Heads Association, said: "I would strongly reject the suggestion that the system is open to corruption. It is good housekeeping to have a reasonable balance ... as a safeguard in times of financial uncertainty."Reuse content