The Government agreed to the procedures, but has since tacked on further stipulations, for example that sickness cannot be an excuse to delay a dismissal - now intended to take just a term.
This week's announcement described the agreement as a "green light" for employers to implement the new "fast-track procedure".
The unions are angry at the suggestion that ill health is used as an excuse and the Government's insistence that it is taking a tough line on incompetent teachers. They would prefer an acknowledgment of their co-operation on the ACAS working party.
In a letter to school standards minister Stephen Byers, Nigel de Gruchy, general secretary of the National Association of Schoolmasters Union of Women Teachers, said: "Your statement represents a poor reward for the teacher unions who played a positive and constructive role in a sensitive area."
Mr Byers was quoted in the Department for Education and Employment's announcement: "We now have an agreement that if a teacher is not up to the job then they must be removed from the classroom. I have instructed the employers to put in place procedures for removing incompetent teachers."
He said he had agreed with the recommendations from the ACAS working party, but added that heads and deputies should be included, local authorities should hold seminars for governors, sickness will not be used as an excuse for delay, and employers will report back on implementation after a year.
Peter Smith, Association of Teachers and Lecturers general secretary, called Mr Byers's announcement "hype . . . and a sick joke".
He added: "For Stephen Byers to be suggesting that teachers are acquiring false sick notes is something for him to raise with the British Medical Association, if he has concrete evidence."
The Professional Association of Teachers accused the Government of "cherry-picking" parts of the working party report that suited them, and the National Union of Teachers also expressed disappointment Schools will be sent a letter from the Department for Education and Employment outlining the agreed procedures and local education authorities will be asked to bring their procedures into line.
Graham Lane, chair of the Local Government Association, said: "With help from the teacher unions we delivered a fair and swifter way of dismissing teachers to a maximum of six months and in extreme cases one month. We have now asked the Government to add a clause to this Autumn's Education Bill to make it compulsory for governing bodies to adopt them."