Michael Portillo, the Employment Secretary, who had argued against the new regulations, has now agreed that there will be new legislation on part-timers' rights in the new year.
Employment surveys show that the proportion of part-timers in teaching is increasing and Richard Margrave, spokesman for the Association of Teachers and Lecturers, said his union had more than 50 part-timers seeking representation after unfair treatment.
He said: "The Government has been dragging its feet in a disgraceful way. We welcome the changes but believe that part-time teachers should have the full range of provisions, for example holiday pay."
Earlier this year, a House of Lords judgment said that present rules breached equality laws because they discriminated against women, who make up more than 90 per cent of part-time workers.