DUP MP Iris Robinson has launched a scathing attack on integrated education saying it is "founded primarily on sectarianism".
Mrs Robinson also said the integrated lobby was discouraging support with the "high handed and arrogant stance perpetually adopted by its public proponents".
She added that it thrived off sectarianism and was part of a wider programme of social engineering driven by government.
Mrs Robinson's comments were made after government rejected a proposal for a new integrated post-primary school Rowallane College.
She said the philosophy of the integrated lobby "consists of nothing else other than self-righteous, pompous claims of reconciliation, no more amazing than claiming they can fit 200 people into the back seat of a Mini".
"Far from transcending sectarianism with some stupendous alternative for the provision of education in Northern Ireland, the integrated lobby is an integral part of that sectarian system and feeds off it without it, it would starve and die," she added.
"It is a philosophy founded primarily on sectarianism, as opposed to the delivery of education and is part of a wider programme of social engineering driven by the government and abetted by the holier than thou section of our population.
"I will, therefore, never act in such a fashion as to further jeopardise the delivery of education to the overwhelming majority of our children, simply to please the politically tainted demands of the tiny minority."
Michael Wardlow, chief executive of the Northern Ireland Council for Integrated Education, said he was surprised by the comments.
"I am not sure by what authority and with what evidence Mrs Robinson makes her claims but it is interesting that she offers nothing except her opinion by way of support for her position," he said.
"It is exactly this close minded attitude where opinion remains the major determinant of action which leaves us without room for progress. Perhaps Mrs Robinson would like to visit one of these schools she seems to like to demonise?"
Baroness May Blood, a dedicated supporter of integrated education, said she had not once heard claims of reconciliation made by the movement.
"Integrated education is about parental choice, religion is not a factor. How can anyone look at the system and come to that conclusion?" she said.
Rowallane College, meanwhile, has secured donations totalling £1 million to ensure it stays open.
Maria Eagle, NIO education minister, said she could not fund the school because it would impact seriously on other schools in the area whose enrolments were falling.
The Integrated Education Fund has agreed to pledge up to £1 million, which includes a $500,000 (£250,000) grant from the American Ireland Fund.
"The finance enables us to plan for the future of the college, and provides peace of mind and security for our current parents and for parents considering sending their children to Rowallane Integrated College in the coming years," principal Dr Olwen Griffith said.