Agreement can be reached over a £150m plan for mixed faith school campuses in North Lanarkshire, the council has insisted.
The St Andrew's and Cumbernauld campus is already up and running
It follows an ultimatum issued by the Catholic Church calling for separate entrances, staff toilets and nurseries at the proposed shared sites.
The church has given North Lanarkshire Council education officials until Friday to satisfy its concerns.
The council said it was puzzled by the move but that a solution was possible.
The church had warned that if written assurances were not given it could withdraw from the entire programme, threatening future projects.
Under the scheme pupils at the Catholic and non-denominational schools have separate classrooms but share the same campus.
The council plans to build a total of seven primary schools.
One campus, which hosts St Andrew's and Cumbernauld primaries, is already up and running in the region as part of the plan.
Church leaders hit out at the final proposals for campuses, agreed by council chiefs, because they ignored their calls for separate school entrances for Catholic pupils.
Other demands by the church included separate staff rooms, staff toilets, gyms and nurseries.
Catholic Church spokesman Peter Kearney said withdrawing support for joint faith campus schemes - which have the backing of First Minister Jack McConnell - was "a real possibility".
He said: "We are at the stage where North Lanarkshire Council are just not budging.
"The authorities are, by law, obliged to provide Catholic schools where they are required.
"The church could have said on day one 'you go ahead with your project but we want our own schools'.
"But we agreed with the plans and now, when the contract is being put out to tender, we find out they have scrapped a lot of what had been agreed."
North Lanarkshire Council director of education Michael O'Neill said he was confident the leader of the council would be in touch with the bishop by the end of the week.
He said: "We will be offering some comments and reassurances which will hopefully allow the bishop to carry on discussing with us.
"It's still quite early, we still haven't decided who the preferred bidder will be and it's at that stage that we would then finalise on details like entrances.
"So, there remains the possibility of finding a solution that keeps the church happy and satisfies the public purse."
A similar joint faith campus was opened late last year at a high school in Dalkeith, Midlothian.
Recent claims suggested violence had broken out between rival pupils in the shared playground but education officials said this was "territorial and not sectarian".
However, Mr McConnell has said he backs the shared campus ideal as part of his drive to stamp out sectarianism.
But Mr Kearney said the problem of bigotry stemmed from the attitude of parents not separate schools.
Lessons remain separate on the joint campuses
He said: "Putting different kids together will not of itself give you harmony because if they go back home and learn to be bigots or racists from their parents they will carry it into the school with them."
A Scottish Executive spokeswoman said the setting up of shared campus schools was a matter for individual councils.
She said: "We support shared campuses where councils think they are the best way to give pupils the facilities they deserve.
"We expect all schools, including joint campus schools, to take account of pupils' and parents' views when making decisions which affect them.
"We believe denominational schools provide an important strand of parental choice in education and make a positive contribution to raising achievement and attainment in Scotland's schools.
"We value their role and expect to see them continue."
Liberal Democrat MSP Donald Gorrie urged the council and the Catholic
education authorities to keep negotiating as joint campuses offered "the best
"They allow the Catholic church to keep its schools with their own ethos and
organisation while promoting good interaction between RC and non-denominational
pupils," said Mr Gorrie, MSP for Central Scotland region.
"It would be a big step backwards in the campaign against
sectarianism, if these joint campuses were scuppered by taking a hard line on
some relatively trivial aspects of the proposal."