Around 93% of school leaders think it is "inappropriate" for the Government to enforce the academisation of primary schools within the next six years, a survey has shown.
A majority of head teachers, their deputies and assistants polled by the National Union of Teachers (NUT) were opposed to current Government education policies and future plans.
Three-quarters said cuts to local children and family service funding were increasing pressure on teachers, while 70% said their school's funding situation next year will negatively affect educational standards.
Nearly all (98%) of those surveyed were concerned about workload and the work-life balance.
Christine Blower, NUT general secretary, said: "These findings are bleak and reveal bitter distrust from school leavers of the direction of travel for education policy in England.
"The Government has the wrong priorities. The strategy of cuts, teacher shortages and far-reaching, chaotic curriculum and assessment changes simply isn't working."
The NUT is holding its annual conference in Brighton until Tuesday.
The academisation plan was announced by George Osborne in his Budget speech earlier this month.
A Department for Education spokesman said: "The fact that almost 70% of all open academies have voluntarily become one suggests the concerns raised by those polled by the NUT are not shared more widely across the country.
"On funding, we are protecting the schools budget in real terms and making funding fairer by introducing a new national funding formula so that areas with highest need attract the most funding.
"We also know unnecessary workload is one of the biggest frustrations for teachers and have done more than ever to tackle this by launching the reports yesterday of the three review groups to address the key concerns raised through the Workload Challenge.
"Rather than simply opposing our reforms, which have already seen 1.4 million more children in good or outstanding schools than in 2010, the NUT would do teachers and pupils a much greater service by engaging constructively with them."