The National Association of Schoolmasters Union of Women Teachers, which wants a working week of no more than 40 hours, said an escalation of its bureaucracy-cutting action is inevitable if the issue is not addressed.
The union wants the School Teachers' Review Body to recommend fixed hours for the working week and the time teachers spend in front of classes when it reports to Government this month.
It argues that English and Welsh teachers are losing out to their Scottish counterparts who are negotiating conditions in the light of the McCrone Inquiry which led to recommendations of a 35-hour week, with 22.5 hours contact time.
Nigel de Gruchy, the union's general secretary, said: "The review body needs to make clear fixed limits and the Government has to accept them. If not, our Time for a Limit campaign will be escalated. We will be forced to impose our own 'Scottish solution'."
He denied that lesson planning and marking would suffer.
The action, yet to be agreed by the union's executive, would probably consist of educing work time gradually to a 40-hour week in the late spring or early summer.
Review body figures show that secondary and special school teachers exceeded 51 hours a week, while their primary colleagues are working an average of 53 hours. This works out at just under 2,000 hours a year, 60 per cent more than their contracted minimum of 1,265 hours.
The review body report last year warned that workload was a cause for concern but was not in favour of recommending a fixed limit.
David Hart, general secretary of the National Association of Head Teachers, said while he had every sympathy with teachers' plight, industrial action would lead to enormous difficulties in schools.
"We really cannot have school management under a regime which sets an artificial limit for some teachers.
"It will cause real problems in schools without making a jot of difference to local education authorities, the department or ministers, who are the cause of the bureaucracy problem in the first place."
Since July, NASUWT members have boycotted administration work and limited the number of meetings attended each week as part of the Time for a Limit campaign.