A planned merger of two primary schools should be postponed until a promised new building is completed, parents have demanded.
Education minister John O'Dowd approved a proposal in late 2013 to amalgamate St Luke's and St Mark's Primary Schools in Twinbrook.
The new school - Holy Evangelists PS - is due to open in September but parents are alarmed that work is yet to start on a new building.
They say they were "sold the idea" that children would be taught in a new building from day one.
Concerns have also been expressed about how the plans were advanced, with parents saying they were not consulted.
The coming together of St Luke's and St Mark's, which are less than half a mile apart, was proposed as part of the massive area-based planning exercise. The schools, which both opened in the early 1970s, were found to have more than 500 empty desks between them.
It is expected that the enrolment number of the single new school will be about 550.
A commitment to build a new school was made by Mr O'Dowd in June last year. From September, both sets of children will be educated in the existing St Luke's building.
The Council for Catholic Maintained School (CCMS) said it held two separate consultations on the future provision of primary education in the parish - one at each school in March 2013.
Minutes from the meeting at St Mark's stated that parents admitted that amalgamation was unavoidable, but parents dispute that the merger topic was even raised that night. They say the hour-long meeting was held to discuss an application for works under the School Enhancement Programme, and not the proposed merger.
A group of parents is now considering a legal challenge. In a letter to parents, the group claimed: "We were not consulted on this planned amalgamation, therefore denied our voice to exercise our rights to decide what is best for our children."
It added: "We are not against the amalgamation of both schools, but only when the new build school we have been allocated for our school is ready for our children. We shouldn't have to compromise on our children's well-being and risk the potential for educational disruption to our children during their important school years."
CCMS said it carried out two consultation events as part of its role in the area planning process.
"On the 25th March 2013, CCMS presented proposals on the current and future provision to the governors, staff and parents of St Luke's PS. The following day, 26th March 2013, CCMS presented the same proposals to the governors, staff and parents of St Mark's," a spokesman said.
"All stakeholders within this consultation process where offered the opportunity to share their views on the proposals."
The Department of Education said work to assess site options and prepare an economic appraisal for the merger project was "well advanced". Minor works are also underway that will allow the St Luke's site to accommodate the new school commencing September 2015.
A spokeswoman said the merger was approved "without any reference to construction of a new building".
"When the economic appraisal has been approved, a professional team will be appointed to take forward the design of the school, following which a procurement for construction of the school will be progressed," she added.
