Scotland's largest teaching union has said it will carry out an escalating campaign of action unless politicians address teachers' "increasingly unmanageable workload".

Teachers are dealing with under-resourced educational reforms, austerity cuts, pointless bureaucracy, rising stress, health risks, low morale, pay cuts, pension fears, supply shortages, uncertain working conditions and excessive hours, according to the Educational Institute of Scotland (EIS).

The EIS council has unanimously agreed to campaign against "excessive teacher workload" and advised that industrial action may be on the table.

General secretary Larry Flanagan said: "At a time when teachers are working extremely hard to deliver an under-resourced Curriculum for Excellence, the largest and most important educational change that Scottish education has seen in a lifetime, austerity cuts have robbed schools of vital resources to support learning and teaching whilst pointless bureaucracy and new demands have increased.

"All of this combines to heap additional workload burdens onto teachers, with consequent rising levels of stress and its associated health risks together with serious implications for overall school morale.

"This significant increase in workload is happening at the same time as teachers are suffering real-term pay cuts, attacks on their pension rights, supply shortages and an ongoing review into working conditions.

"Even with teachers already working excessive hours beyond their contract, the stark truth is that not everything can be achieved. We are calling on both Scottish and local government to work with us to address this issue as a matter of priority. A failure to do so on their part will see the campaign escalate over the months ahead.

"It is important to remember that the working environment for teachers is the learning environment for young people, so it is essential that these issues are tackled to provide all young people with the best possible environment for their learning."

An EIS spokesman said the form of industrial action has yet to be agreed and could include letter writing and lobbying of local and national politicians.

He said: "Industrial action has not been ruled in or out at this stage. The campaign itself has still to be fully developed. It's been approved by our council and it's now for our staff to decide what action they will take in the days ahead."