Britain’s two major teaching unions have started the clock ticking on industrial action for schools in England and Wales after votes at conferences in Birmingham and Brighton.

Delegates at the National Education Union (NEU), the section of the newly merged union formerly known as the National Union of Teachers, backed a motion in Brighton to proceed to a ballot of members over possible strikes.

Meanwhile, delegates in Birmingham at the NASUWT teachers union unanimously agreed to support industrial action if the government maintains its cap restraining pay increases for teachers.

Both unions heard impassioned speeches on the need for pay rises to compensate teachers for years of austerity, and to stem the flow of teachers leaving the state sector because of heavy workloads and more attractive options elsewhere in the labour market.

“Staggering from year to year making paltry single percentage offers will not address the problems. Teachers will continue to leave the profession and potential recruits will be deterred from entering it in the first place,” said Chris Keates, general secretary of the NASUWT.

A Department for Education spokesperson said record numbers of teachers were working in state schools in England, with an average salary of £37,400 outside of London and nearly £41,900 in London. “We have already given schools freedom over staff pay and have asked the independent School Teachers’ Review Body to take account of the government’s flexible approach to public sector pay as they develop their recommendation,” the DfE said.

“We want to continue to attract and keep the best and brightest people in our schools. That’s why the education secretary recently announced a strategy to drive recruitment and boost retention of teachers.”

NEU delegates were told by Anne Lemon, a member of the union’s executive, that they should follow the industrial action by University and College Union members, which included 14 days of strikes over pensions changes last term.

“One-day strikes will not cut the mustard,” Lemon told delegates.

Kevin Courtney, the NEU joint general secretary, said his union “will prepare to consult members widely on the action we need to take in order to win these demands and solve the teacher recruitment and retention crisis”.

For procedural reasons, any strikes are unlikely to take place before the end of the calendar year.

The NEU motion is likely to be followed by a similar motion at the other branch of the merged union, the Association of Teachers and Lecturers, which meets next week in Liverpool. The two motions would need to be spliced together and approved by the NEU’s joint executive.

The NEU motion commits the union to holding an indicative ballot of members this summer, which if successful would be followed by a formal ballot of members, possibly in the autumn.

Under new rules governing industrial action, a successful strike ballot needs at least a 50% turn-out of members, and a majority amounting to 40% of the total membership in order to be carried. For example, a 50% turn-out in voting would require 80% of votes in favour of striking for it to clear the 40% threshold.