From Washington, where he is attending a US investment conference, Mr Robinson defended his remarks calling for an end to segregated education in Northern Ireland and likening the current system to benign apartheid.
"It isn't a matter of opinion; it is a matter of fact", Mr Robinson told UTV. "The issue is whether we want to do anything about it or not, or whether we're going to allow vested interests to stop us from having the kind of united society that we need in Northern Ireland".
"Does anyone really believe that it is good for our society, for our children to be educated separately, for them to grow up with a 'them and us' attitude to their fellow citizens?
"If those responsible for Catholic education believe it is, I think they're vastly out of touch not only with what the people of Northern Ireland say, but with everybody who has looked at the educational sector recognises to be the case."
Mr Robinson says between 70%-80% parents in Northern Ireland want their children to be educated together.
"Maybe they don't count", the DUP leader said.
Mr Robinson said he did not object to church-run schools, but objected to the state funding them.
Sinn Fein's Education Committee member John O'Dowd has slammed his remarks.
"Mr Robinson has to understand that over 50% of our children are educated in Catholic schools, you cannot do away with funding for the sector because our educated system would collapse and our Executive would go bankrupt," Mr O'Dowd told UTV.
The Chairman of the Catholic Principals Association of Northern Ireland, Seamus Quinn, branded the comparison with apartheid "really offensive".
"The Catholic sector has moved tremendously in recent years to become more welcoming, and to turn around and denigrate the attempts to become more integrated is extremely unhelpful.
"As a strong and confident education system, we are not intimidated or frightened by any of the comments Peter Robinson made - we are just saddened that someone who purports to represent all the people of Northern Ireland has chosen to attack one sector," Mr Quinn said.
A number of SDLP representatives are set to meet with the chairman of the Commission for Catholic Education to discuss the impact of Peter Robinson's remarks.
Bishop Donal McKeown has already criticised the First Minister's comments and insisted the choice of faith-based education for their child was a "fundamental right of parents", while SDLP leader Margaret Ritchie accused Mr Robinson of taking a side swipe at the Catholic education system.
"It took decades of sacrifice before Catholic parents were able to get proper funding for their schools. Our divided society is not the result of Catholic education and if the First Minister is serious about wanting to tackle division he really needs to find better ways of going about it", she said.
While Mr Robinson has come under fire for his speech last week, he has also received backing from some sectors.
The CEO of the Council for Integrated Education, Noreen Campbell, said the First Minister had "done us a favour" by putting the issue into the political spotlight.
The Alliance Party's Education spokesman, Trevor Lunn, has accused the Northern Ireland's two biggest parties of "bickering" over the issue.
But addressing what he calls the "irony" of a bid to end segregation dividing politicians along party lines, Mr Lunn has said it is time to get serious about the issue.
"This must not be about attacking one sector or another. It must be about having more sharing or integration," he said.
Meanwhile, UUP Education Spokesperson Basil McCrea MLA says Ulster Unionists support shared state funded education, but question the First Minister's motivations.
"There is no doubt that Peter Robinson has provoked controversy and I hope that this was not his sole intention. Ahead of the Comprehensive Spending Review and an election headlines are helpful for any political party but they alone cannot deliver change", Mr McCrea said.
On Friday, Mr Robinson called for the creation of a commission to bring forward recommendations to implement integrated education across the region.