The NASUWT union has demanded an above-inflation pay rise for teachers next year to address a "significant cut" in their real-terms wage packets over the last six years.

Successive years of real-terms reductions are having an impact upon teacher recruitment, morale and the attractiveness of the profession, the union claims.

It also argues individual teachers are tens of thousands of pounds worse off as a result of the cumulative impact of successive years of pay freezes, below-inflation increases and a rise in pension contributions.

Union bosses have sent a 26-page document to Education Secretary John Swinney to press their case for "substantial improvements to teachers' pay and conditions" in 2017/18.

As well as calling for a pay rise, the union has proposed a raft of other changes, including removing a cap on short-term supply teachers' pay and restoring certain maternity entitlements.

They also call for teachers not to have to carry out administrative duties "which do not require the exercise of their professional skills and judgment", legislation to establish key teachers' terms and conditions as statutory entitlements and a strategy to remove the need for teachers to cover for colleagues who are off.

The union argues teachers have been increasingly diverted from their teaching role towards administration tasks and having to cover for absent colleagues.

NASUWT general secretary Chris Keates said: "The NASUWT's correspondence to the Deputy First Minister provides comprehensive evidence of the impact which successive years of real-terms cuts to teachers' pay are having on recruitment, retention, teacher morale and the attractiveness of the profession.

"Teachers in Scotland are tens of thousands of pounds worse off as a result of the cumulative impact of successive years of pay freezes, below-inflation pay awards and the rise in pension contributions.

"The cuts to pay and conditions over the last six years have come at a time when teachers have been pulling out all the stops to ensure the success of major changes to the curriculum and qualifications systems, and when they are facing yet more reform as a result of the Scottish Government's highly ambitious national improvement framework."

She said the union supports ministers' plans to raise standards in schools and narrow the attainment gap but added: "The NASUWT believes that the Scottish Government must now demonstrate its support for teachers by providing them with the pay and working conditions which enable and recognise their vital role in shaping Scotland's future economic, cultural and social success."

A Scottish Government spokeswoman said: "Teachers' pay and conditions of service in Scotland are matters for the Scottish Negotiating Committee for Teachers.

"SNCT negotiations will commence towards the beginning of next year on the teachers' pay award from April 2017 and we would encourage the NASUWT to participate fully in this process through their membership of the teachers' side.