By Justin Parkinson
BBC News education reporter at the ATL conference
Teachers are calling on the government to end all state funding for newly created faith schools by 2020.
Secular and faith schools should co-exist, said delegate Chris Wilson
The Association of Teachers and Lecturers' annual conference heard they could be "an assault on tolerance".
But some delegates in the conference hall at Gateshead said the ATL's motion was itself intolerant.
The Department for Education said faith schools were popular with parents, played a valuable role in local communities and promoted inclusion.
A spokesman added: "The major faith leaders only recently reaffirmed their commitment to ensure that faith schools teach pupils about all major religions."
The conference voted against another proposal calling on the government to "legislate to prevent the growing influence of religious organisations in state schools", including the influence of "creationism or intelligent design".
'Sleepwalking to segregation'
Delegates criticised the sponsoring of city academies by religious groups such as the Emmanuel Schools Foundation in north-east England, established by Christian car dealer Sir Peter Vardy.
It was claimed that government plans to set up "trust" schools, in England, with more say over their own running, could increase conflicts between faiths.
Hank Roberts, from Brent in London, who proposed the motion, said: "Massive forces and billions of pounds are being mobilised and spent in a worldwide assault on tolerance, secular education and scientific rationality."
He added: "Do we want to see a proliferation of state-funded religious schools?"
Mr Roberts also said: "We are in danger of sleepwalking to segregation."
But Hilary Jones, a teacher from Thameside, said the resolution was "simply expressing a prejudice" against religion.
Liz Butler, from Northumberland, said it seemed like a "dictatorship".
But Chris Wilson, a college lecturer from Cambridge and a Unitarian minister, said it was important to maintain the "post-war settlement" of secular and faith schools co-existing.
Wearing his clerical collar, he added: "We want a culture that breeds diversity and which nurtures respect for all faiths and traditions."
He said schools were not places for "fundamentalist views".
Earlier, the ATL conference voted that young people should have a "right to childhood", away from adult problems such as drugs and financial problems.
One teacher said that a nine-year-old in her class, when asked to write a poem about her biggest worry, described her parents' problems with mortgage payments.
The conference runs until Thursday.