Teachers are threatening strike action in their campaign against excessive workload.
The National Union of Teachers' annual conference has called for "sustained strike action" to back schools challenging a long hours culture.
The union says teachers' workload is "intolerable and getting worse".
The Department for Education said rather than threatening "unnecessary strike action" the NUT should "work constructively" on a solution.
As the NUT conference in Brighton voted to campaign over the "workload crisis", the Education Secretary Nicky Morgan announced proposals to tackle excessive working hours for teachers in England.
These plans call for schools not to adopt "emerging fads" which can mean "excessive marking" for teachers and unnecessary data collection.
It also warns against schools encouraging excessive "gold plating" approaches to marking.
The government's workload plan would require head teachers to take more account of the impact of marking on teachers' time and to prevent "unreasonable demands".
It also calls for adequate planning time when changes are being introduced in schools.
"Nothing is more damaging to the profession than wasting the passion and expertise of teachers and school leaders on unnecessary tasks," said Mrs Morgan.
She said the proposals would address the three biggest concerns about workload - marking, planning and data collection.
The NUT welcomed Mrs Morgan's reports on tackling workload.
But the teachers' union conference backed calls for "sustained strike action" in support of schools seeking improvements in workload.
The NUT conference supported warnings over the "perfect storm" on workload, which delegates said had been exacerbated by teacher shortages and rising pupil numbers.
Delegates said teachers were now working 65 to 70 hours per week in term time.
And they argued that it was one of the most common reasons for teachers leaving the profession.
Sheila Caffrey from Bristol said that the six words that were most likely to raise teachers' stress levels were: "You only work until three o'clock."
Kenneth Rustidge, from the union's executive, said excessive workload had become a major disincentive to people who might have entered teaching.
The conference backed calls for more teachers, lower class sizes, less teaching time and more time for planning.
NUT leader Christine Blower said: "Teachers speak of having no life outside of school, nor time for family and friends.
"We are not talking about having to stay a little bit later of an evening, but of workloads that keep teachers working into the night and at weekends."
A Department for Education spokeswoman said: "It's a shame the NUT has chosen to threaten more unnecessary strike action rather than working constructively with the government to address teachers' concerns.
"Today's announcement of new steps to reduce unnecessary workload shows what can be achieved when we work together.
"As set out in our White Paper we are determined to continue with our vision to ensure every single child has the best possible education, as well as raising the status of the profession. It would be refreshing to see the NUT doing likewise."