Nicky Morgan has used her first party conference speech as education secretary to shower love on teachers, promising to make it a priority to reduce their workloads.

The new cabinet minister’s promise to tackle the issue comes after the National Union of Teachers threatened strikes in response to a survey showing a “shocking and sobering” workload crisis in schools.

Her speech at the Conservative party conference was in direct contrast to the tone of her antagonistic predecessor, Michael Gove, who once denounced striking teachers as the “enemies of promise” and was moved to the role of chief whip in the last reshuffle.

Morgan spoke of teachers as “heroes”, marvelled at their dedication and claimed she cared for each and every school.

However, critics point out that Morgan has pledged to carry on all the controversial reforms of Gove that have added to teachers’ worries.

Addressing the conference in Birmingham, Morgan paid tribute to Gove’s “passion, conviction and leadership”, leading to cheers and lengthy applause from the audience that far exceeded the reaction her speech received at the end.

In her message of support to teachers, Morgan said: “If our school story has a hero, it is them ... Sometimes perhaps we take it for granted. We forget that teachers are not just teachers: they’re also friends and relatives. Mothers and fathers, sons and daughters, brothers and sisters.

“And when I hear of teachers working late into the night marking books, planning lessons, preparing for inspections that may or may not come, I do two things: I marvel at their dedication. But I also think, there must be a better way.

“I don’t want my child to be taught by someone too tired, too stressed and too anxious to do the job well.”

She said her first priority was to reduce the overall burden on teachers and second to ensure that teachers spend more time in the classroom teaching.

After a brief attack on Labour, claiming the party lowered school standards, and her opposite number Tristram Hunt for being a “part-time politician and full-time celebrity historian”, she set out her vision of a school system in which pupils are not only challenged academically but well prepared for work.

“From birth to adulthood – throughout the education system – our mission is to ensure that every young person has the best chance to overcome the soft bigotry of low expectations – the culture of “can’t” – and to fulfil every ounce of their potential,” she said.

Labour’s Hunt said the Tory-led government has already “damaged school standards by allowing unqualified teachers into the classroom, pressing ahead with the failing free schools programme and having no plan for the forgotten 50% of young people – those young people who do not wish to pursue the traditional academic route.”

“Labour will drive up school standards,” he said. “We will end the free school programme, prioritising capital investment to overcome David Cameron’s primary school places crisis that has delivered a 200% rise in the number of infants being taught in classes of more than thirty pupils.

Chris Keates, general secretary of the NASUWT union, said her union was pleased by Morgan’s recognition that their professional lives are blighted by excessive workload and her commitment to address this. “But tackling workload effectively will require the secretary of state to recognise the contribution of this government’s policies to the current excessive workload burdens,” she added.