Scotland's main teaching union has agreed to hold a ballot on boycotting the development of the new curriculum.
Delegates at the EIS conference in Perth said the Curriculum for Excellence changes were being brought in too quickly, increasing workloads and damaging pupils' learning.
Teachers voted against targeted strikes over pay and conditions.
The union's leader Ronnie Smith warned of dark times ahead as councils seek to make savings.
The ballot on boycotting some development work on the new curriculum will be held in November.
Introducing the boycott motion to conference, Michael Dolan, from West Dunbartonshire, said changes to the curriculum, teaching methodologies, assessment methods and reporting on pupils' progress to parents were "all too much".
Teachers are being "asked to plan for changes before anyone can tell us where we are going".
He said: "It's all too much and there's not enough support and time to evaluate the effects and implications of the changes. We do need to be given proper time and resources to implement changes.
"In education, we can't afford to get it wrong. We can't experiment with the education of a generation of young people."
A separate motion to suspend the Curriculum for Excellence because of massive cuts to education was also carried by union members.
In his address to conference EIS leader Mr Smith warned of the difficult times.
He said: "We are far from seeing the light at the end of the tunnel. We face many more and serious challenges ahead."
The Scottish Government has commissioned Professor Gerry McCormac of Stirling University to review teachers' pay and conditions.
Mr Smith added: "Most immediately we face what may flow from the McCormac Review.
"It is unfortunate that this review is working in such a straitened economic climate and I welcome the assurances they have given us that they will not be a stalking horse for a cuts agenda."
'Excellent work of teachers'
Education Secretary Mike Russell said he would meet with representatives from the EIS.
He added: "Speaking to teachers across Scotland there is clear support for Curriculum for Excellence and a clear recognition of its vital role in raising ambition and attainment levels in our schools.
"The EIS has again today signalled its ongoing commitment to teachers and Curriculum for Excellence in the interests of pupils.
"We will work with them to ensure we continue the excellent work of teachers delivering Curriculum for Excellence in all our schools while recognising the issues which are currently being considered by the McCormac Review."
EIS members also approved a motion to demand that the Scottish government increased the amount of money it is spending on its Curriculum for Excellence.
The motion said the government should set aside "adequate resources" needed to implement the changes.